when will SHE let us know to let her out?

Most dogs don't tell you they have to go. Once she is 100% trained if she has to go out for say an emergency she will do stuff like, paw at you or whine, or do circles. But if you just keep her on a schedule you won't have to worry. Some have trained to ring a bell, some do bark, but w/ the schedule she won't need to.
I don't know about a pup her age, but with my two adults, I do 5 am (because that's when I get up)
then, hubby takes them at 7 for a poop then 12pm then I like to take them for a walk at  2pm, then 7pm and they go to bed.
I agree I get more upset, and worried about the dogs then I ever have w/the kids. I think it's the different species thing for me.

She may never develop to this point.  Best course of action is never to rely on her to and as deb says keep her to a schedule.  A lot of dogs that do "tell" you don't start "telling" you early enough and are already pretty desperate, so accidents happen and training is impeded.  At 12 weeks I'd be taking her out more often than that, just to be on the safe side .... 2 hrs would be the maximum, not the minimum.

We got our pup at 8wks and like you, learned quickly that you have to take them out CONSTANTLY.  Playing, sleeping, eating, drinking, or just the passing of time = out to pee!  At 12wks we decided the pup was so smart that he would be able to tell us he had to go.  Well he walked by the front door and then came over to us and squatted on the carpet.  To him, at 12wks, his signal was simply walking by the door and we didn't pick up on it.  So much for letting him tell US. 
For the first good chunk of time, YOU tell your dog when to go, and by doing this all the time, you're constantly hammering home the pattern of "outside to go pee".  Since you're so vigilant (and congrats to you, you sound good at this!), he doesn't have accidents which only serves to further reinforce the idea that he can only pee outside. 
Our pup is 4 months now, and when he has to pee he goes to the front door, sits there and looks at you.  Sometimes he whines at the front door.  He has gotten the hang of it so we no longer need to tell HIM when to go.  Just keep doing what you're doing and eventually it'll just happen.  There's no set age because all dogs and breeds are different. 

Just a word to the wise, by the time she's clever enough to let you know she wants to go out to otty, she will be clever enough to let you know she wants to go out to pretend to potty and just play instead. The goal of housetraining is just to have a dog who holds it until let out, simple as that.

Yeah I've never really put too much emphasis on a dog letting me know when he wants to go. The dogs are on a pretty regular schedule for potty trips and the emphasis in our house is the dog holding it until that time. If it's a dire emergency, they each have thier own special signal, but otherwise no (Conrad whines and paces and pants, Marlowe just kind of dances around and wags his tail more vigorously than usual). They just hold it until they get let out (ideally--Marlowe's still a work in progress).

Marlowe this morning ran into the bedroom and jumped on the bed at 2 AM. This is VERY unlike him. He sleeps solidly from 8 PM until 7 AM and even then I have to pry him loose from the couch. I took that to mean EMERGENCY!!! and I got up and let him out and sure enough, it was major poop time. That's all I ask for in my dogs. Just let me know if you're sick or about to burst, but otherwise, about every 4 hours when we're home you'll get your chance and just please if you can quietly hold it until then.

We're in exactly the same boat with our 12 week old pup. She definitely knows now that going out means time to pee. She still has a few accidents from time to time, when we're not expecting it, or not paying attention.

One way to reduce your stress is to crate her when you can't keep an eye on her - our pup now avoids going in the crate so that can give us an hour or two of relaxation without having to watch her every move.

We're going to start seeing if ringing a bell at the back door whenever we take her out helps her learn to do that on her own.

I did the bell thing and it worked for a week. Then theystarted ringing it anytime they wanted out to play. Now I tell them when to go.

Letting your dog tell you when she has to go outside?

That's a lot of agency to give a twelve week old dog, don't you think? If I were twelve weeks old and a dog that has no concept of inside and outside, much less a general sense that one pees outside and not inside, I don't think I could be trusted to tell you that I needed to go outside to pee.

...but I would definitely learn that it's a fun game to get you to let me out all the time.

It just happened naturally for us. We stick to our schedule, which is letting her out when she wakes up in the morning, before I leave for work, at lunch, after work, after dinner, before bed. Beyond those times, if she wants to go out she sits at the door and touches the doorknob with her nose. I always make her sit before going out so I guess that's the habit she's picked up. Don't stress it - it will happen naturally.

I am working on housetraining our 5 month old lab.  We got her in November and have made a lot of progress since the start, but we aren't quite there yet.  When we first brought Kimber home she would "go" anywhere/everywhere including inside her crate. We had her checked for a UT infection and got that treated.  (Who knew that switching her to a high quality food from a low quality with different pH would cause the UT? - Not us).  Now we have finally gotten her to the point that she no longer has accidents in the crate[], and will go as soon as we take her outside after coming out of her crate.  I am just hoping to make it to the point that she is able to hold it and understands that she is not allowed to go inside.  At what age do they normally know to hold it?  Is it different between small and large dogs?  I will be so happy when she stops having accidents and is reliably housetrained.  I have to admit that I am really jealous when I hear people say their dog was housetrained at 10 weeks.  Everyone in our house is really dedicated to this training, so we are looking forward to seeing the fruit of our labor[]
 
Oh and the other thing she does is that she always goes on the concrete instead of the grass.  How/When can we get her to change?
 
Thanks Everyone

PLease post a pic of Honey.  I think my dog is part ES and would like to see a puppy pic.
 
My 10 month old still has accidents all the time.  I taught her to ring a bell on our bedroom door.  Yes sometimes its a false alarm but ususally its the truth she needs to go.   If I just cant get her to go for the last pee 9Pm or so,  I crumble up a king size sheet on top off a double folder thick towel for her to  pee on in middle of nite in my room.   She sleeps on our bed.  I don't worry about it,,,,I know it will happen one day  LOL  and I resigned to replace the carpet in the bedroom in a year or so . 

You could also teach her to ring a bell to let you know. I taught my dog to do it when he as about 3 months. Soon he learned to ring it every time he wanted to go out to play in the yard (so he wouldn't stop ringing the damn thing). He got better at not crying wolf [], you just have to watch out for that!
Get a little bell in a bird section of a pet store and tie it on the door, by the door, etc. I hammered it down with a nail in the wall beside our door. Every time we'd come out, I slightly pushed him to it, or made him walk right by it so that it wrung... There are so many ways to teach that - plain old Pavlov's conditioning with bells!

Oh and the other thing she does is that she always goes on the concrete instead of the grass.  How/When can we get her to change?

That's pretty common IME.  Dogs learn to eliminate in connection with a substrate - that is, not only do they think "oh no i need a wee, find grass" they also think "oh look grass I need a wee".  Likely, it's being on the concrete which is stimulating her to need to go.  A lot of dogs do generalise this to just "outside" .... our last pup was exactly like this and gradually became less fussy about the surface she went on provided it was outside.... but then we have a little bit of yard outside our door and grass beyond that so the grass was always very close by, this might not have happened if the two were more seperate.  IMO her being so fussy about the surface she eliminates onis a GOOD sign for housetraining, in your position I wouldn't worry about it too much and trust that she will probably get less fussy in time.... is it a major problem if she won't use grass?    After all it will stay lovely and green.  And you can hose the concrete down to keep the area clean which you cant do with grass.

we actively discourage the dogs from "asking" to go out. They'd be going in and out every five minutes, and I'm not a doorman. A truly housebroken dog holds it as long as is physically possible, and waits to be taken out. We start out taking pups out every hour on the hour, and gradually increase the time between trips outside.