do you have a weight? check out beautiful dragons they have some growth charts on the website. don't worry so much about age compared to weight to length. all bearded dragons grow at different weight. what you feeding him? if your worried about him groaning some more switch from crickets to dubia roaches! trust me i did now my female who is 15.25 inches and 239 grams is growing still like a weed! dubia have such a better meat to shell ratio. also check out some phoenix worms, beardies love them but they are pretty expensive esp when mine goes through about 1000 in 2 weeks along with all the dubias she can eat!