Is there something wrong with my albino rat?

I just recently bought a new rat for my 1 year old rat. she is very young, little and skinny. she seems shy but every so often seems to pop out a smidgin from her shell. her eyes are half closed alot. when i let them out to play she wont roam yet come to me and fall asleep hiding her face. but she is not social much. she is sharing a cage with her new bigger roomy and i am afraid there may be something wrong with her. she is albino. is there some kind of illness she may have? sleepy all the time cause she is really young? or just really shy and scared? (we had here for about 3 days now). (i bought her at a petco, she was with three other rats her size.) she is a medium size rat.