I'm afraid that I'll catch a Chickenpox?

I'm almost 15, and my sister just got a chickenpox and it hurt her at the first days. I stayed away from her so I won't catch it because I don't want to skip school for so many days. Is there is anyway to not catch it for the rest of my life? or is it possible to get just little? I mean I saw my sister her body if full with blisters and it looks like they're not gonna fade. Gosh I'm really scared can you guys give me any infos about this that would help me if I got it.. It looks like it hurts so much :(