How to be more confident and charming?

[RooRoo]

I'm a 17 y/o girl with long blonde curly hair, deep dimples, pale skin, and green eyes. I wear makeup and do my hair everyday so my looks are not the issue. I know I look decent but I still lack confidence. When I'm at home I can look in the mirror and be pretty happy with the way I look but when I'm out in public I find myself constantly checking my hair and makeup in the reflection of my phone. I am wayy too nervous to hangout with guys because I am absolutely terrified of awkward moments. I worry that they will think I'm ugly/annoying/boring and then never talk to me again. I've never had a boyfriend and I really don't want one because I just get too nervous when it comes to guys being close to me.
I have some major anxiety issues and whenever I am around someone that I barely know my mind goes completely blank and all I do is nod or give a sort of half smile. I’ve asked many people for advice but all they tell me to do is ‘be myself’.. But I have no idea how to do that when I don’t even know who I am. I barely have any friends and the few I do don’t even hangout with me. I’m much more popular via internet than I am in real life. I have a LOT of tumblr, instagram, and twitter followers.. and there is many guys that go to a neighboring school of mine that I have met via Facebook that would like to hangout with me but I just keep finding excuses to not do it.
(They aren’t some creepers with fake profiles, I’ve seen them in person at different events, but never actually met them.)

[Mary]

STOP! you need to stop hating on yourself. i hate when people do that. i get nervous too, just as nervous as you. but think you have friends and the only way to be confident is to be arrogant and annoying. every one fakes confidence well the ones that LOOK confident and charming. you don't fit in with the crowd, the crowd fits in with YOU.

[Cookiez]

Usually I would say "be yourself" but I know what you mean when you say you don't know who you are. No one really knows who they are until waaaaaaaaay later in life!
I suggest you find something that interests you (for me it was astronomy, books, music, and photography<<I know I'm a geek ). Surround yourself in that interest and within that, you'll find who you really are!
Hope this works for you like it did me