67lbs is very average for a smaller female Shepherd, so I wouldn't worry about anything.  Not all GSDs are meant to be 100+ lbs.  In fact, I only know one (a male) that is that large, and he is a BIG boy.  You don't want your GSD to be fat as it will only lead to joint problems & the like down the road.

When I got Luke (GSD/Lab) from the Humane Society they told me, "Oh, he'll be about a 60/65lb dog when he grows up."  Yeah.....  He ended up a 90lb lean mass of muscle, 27" tall.

Sometimes they just end up a bit bigger or smaller than we thought, but we love them all the same!