Will my belly piercing get infected?

I pierced my belly button with a kit I bought online, it came with a 14g needle (sterilized), clamp, and, the aftercare stuff. My friend who has pierced belly buttons before pierced it for me and it isn't crooked, plus everything was sterilized... Should I still be worried since it wasnt done professionally? Any tips on aftercare? Thanks. I'm 14 by the way.