Hey man,
I'm 19 too and I've been wearing for like three months. I still have a fair bit of hair on top, just no hairline and a thin crown. I remove every 2 weeks and the growing hair isn't that big of a deal. You will want a lace unit for the hair to grow through so the glue stays strong. Sometimes the hair might loosen an edge, but you can shave that spot and re-glue if its that big of a deal. I usually only re-glue the hairline if it loosens and don't worry about the back and sides. If you have people feeling your scalp all the time then remove weekly and no one will feel any growing hair.