The most adult thing a 16 year old could do is to put together a look that does not fall in line with your friends/peer group. I'm not religious, but i went to chuch this past weekend, and i noticed an entire row of "boys" about your age all of which had the same haircut (some shaggy looking, poodle mess).
Pull up a picture of brad pitt or george clooney and see if they have this same hairstyle. Or i can save you the time and just tell you they dont.
So, any 16 year old with the guts to still look good, but different than your friends, would be quite impressive, from a mature/manly point of view. But i'm 35 so what do i know, right? ;-)
As proof of this, check out any "DJ" that's 20+ ,and you see "men" finally pick up on this and usually begin to develop their own personalized look that's only them, and no one else.
Also, keep learning about women, and do everything you can to not be afraid of them. Its much better to keep meeting different women and even making mistakes than to just be afraid of them and not do anything at all.
Azanon