So "peaked" is definitely not the right word for the context that's being used here.
What I think is trying to be said is that Aaron is "entering his PRIME"...and is getting to the best of his abilities(physically, mentally etc) and hitting his stride.
Entering his Prime and Peaking are not the same thing.
Entering his Prime means that Aaron is getting into his best years as a quarterback and playing at a very high level and beginning to reach his potential.
Saying he's PEAKED means, his abilities cannot get any better, and has already reached his potential. You're saying Aaron's hit a ceiling. NOT a compliment.
If you're saying he's entered his physical prime, I would agree, because he's definitely playing at a high level and his skills are becoming elite.
If you are saying he has PEAKED physically, you are stating that he has reached his physical limit and cannot get anybetter.
I completely disagree w/that.
Aaron's 26-27 years old. Athletes actually enter their physical prime around 28-32. Aaron's this good and has not quite even gotten there yet.
And w/the way athletes train and maintain their bodies, they can extend their prime years into their mid 30s (see Peyton Manning, Tom Brady).
So in conclusion, has Aaron entered his prime years? You can possilbly say so. Has he reached his potential as a QB and cannot get any better?
Not by a long shot. He's still learning, getting stronger, and getting smarter in the game. I would say it's way too premature to say a 26-27 year old QB has PEAKED in that way.