Congratulations on his good health!
Well, the good news is that he is healthy. Petsmart prices are often outrageous, but getting a healthy cham from them is an achievement worth celebrating.
The fact that you purchased him as a juvenile actually works in your favor. He has had a chance to develop and grow under your care, which is far better than suffering at the pet store for a year. Most keepers prefer to raise their own, rather than take on the results of someone else's neglect.
Also, you have a better chance of forming his personality and bonding well with him since you purchased him young.
In most cases, youth would only be considered a problem for someone who wanted an adult for breeding purposes.
Did the vet weigh him? How heavy and how long is he?