My hair stops growing after a while

I'm 15, african american and I have real short hair. less than 5mm at full growth.
My hair, after about 2 weeks, stops growing. I don't have a hair loss problem what so ever but i'm concluding to myself that maybe my genes permit my hair from growing anymore

My question is, is there anyway, through any means that I could get my hair to grow? Maybe through chemicals or such? These days, herdity seems to be be outmatched .

I so very much want exceptionally long hair al la dreds, or curly long hair.