What McGrath said above, Guest.

I grew mine (OKOK, McG, I *let* it grow) at approximately your age; and have kept it faithfully (never shaven off; occasionally trimmed, washed once or twice:) for lo these 35 years since. / For us un-hirsute fellers it can be silly & scratchy at first; but give it a fighting chance. / My hair's medium brown & straight; youthful beard came in quite wiry & distinctly reddish. Go figure. (Celtic gene mutations?) Going grey now; but don't worry about that, kid, you got lots of time. Good luck.