Midget Bearded Dragon?

So I've had my husband's bearded dragon for a year now. We got him in November from a Petco and I assumed he was a little under a month old at the time so he has to be over a year old now. However, he's still about the same size as a juvenile bearded dragon. I still call him the "baby lizard" because he's so small! Or maybe my perception is off because my adult female, Damien, has some German Giant in her and she's naturally a larger bearded dragon, but I swear the other one should definitely be bigger at a year old...

I took pictures of them side-by-side for comparison. Damien is about 19 inches (18 now, tailtip fell off from tail rot), haven't been able to get the baby to sit still long enough to measure him.



He's a healthy lizard by any means, active, curious, good fat pads and no signs of MBD.

Some care specs:

Reptisun 10.0 tube
60w basking bulb (100 degree basking spot, 75 in cool area)
20 gal tank (this is going to be replaced around the 1st, recently moved to a new state and could only take the small tank he had as a baby for him)
Only paper towel substrate all his life, I haven't changed it because I still consider him a baby I might change it to soft towels soon because he likes to burrow in my blankets and clothes.
Bok choy and romaine lettuce finely chopped every day
He WAS getting mealworms and the occasional wax worm for the first couple months because it was the only thing our pet store offered, but I just ordered the soft bodied value pack (silkworms, reptiworms, wax worms) from a bug breeder online so my beardies will be going from superworms/mealworms to soft worms.
Deficates once every 1-3 days, soft urates and a greenish brown color with a good "seal".

I just feel like something stunted his growth because when Damien was a year old, she was as big as she is now. And he's half her size! I gave her the same care as he did, so let me know if something's wrong with my husbandry...or if he's just a small lizard? :S

Well Petco doesnt really get their herps from reputable breeders so I would assume their would be a difference between good breeding and bad breeding when it comes to size, but every beardie is different! He looks really healthy so I wouldnt really worry about it.

When I was a lot younger I got my first beardie from Petco and he did not get that large in comparison to my newest beardie who is from a good breeder and is 5 months old and already 19 inches.