hard to shave

I just tried shaving down there and I'm 13 and it's like the second time I have done it. there was tons of hair everywhere and I tried getting it all without cutting the inside part and I couldn't get all the hair. it's growing on my thighs too and I shaved over some of it but it wouldn't come off. and on the lips, the hair grows on the very edge of it so I'm scared I'll cut myself and that would be very bad. please help I don't really know what to do or how to get rid of it. tips?