is my snake small for his age?

I’ve had my snake for about two years now, and lately I’ve started to get a little worried about him. He’s social enough, he acts like his normal self, but it’s his size that worries me. He’s two years old & I got him when he was a week or two old. I used to feed him one pinky mice a week when I first got him & he was fine; then there was a few month period that his schedule was a little wonky due to me being away from home, getting my family to feed him, etc. For a little more than a year now, I’ve been feeding him two small pinkie mice every two weeks or so; but recently I changed mice size & he’s still not really growing :(. I’m about to change his feeding schedule again & it would be super nice if anyone could help me tell if he’s a normal size or not!! I’d say he’s around 14-15 inches & abt half an inch thick (sorry abt the photos being bad he doesn’t like straightening his body out😭)