as long as the snake is in good condition and it is what you want...then were you buy it isnt an issue...as for age...I prefer babies, because well it is easier to understand what they do in the future if you already know their past. As for grown ones...who knows what they have been through?
also I just like watching them grow...mine has gone from 13 inches when i got him to a bit over 36 inches now.
Better quality for morphs is found usually online through big time trusted breeders.
NERD
NextWorldExotics
RMJReptiles
Glass Reptiles
The Snake Keeper
8BallPythons
RalphDavis
Graziani
Brock Wagner Reptiles
WestCoastJungle
....just a few of the many