sexing

[skillz]

Hey, i have a quick question..when i got my little guy he was about 4 weeks old...i know thats to young but they had about 30 of these guys in a pet store and i had to get one anyways...i asked they guy for a male...he goes in and about 2 mins later says he got me a male. I was just thinking about how likely that is to figure out when there that young. Mabey it is and i'm not thinking straight but thats my question to you guys....is it possible to tell at that young of an age?..thanks