Why can't I like anyone?

Ok,this may sound rather pathetic but i have some self asteem issues and theyre getting in the way of ever having a relationship.I always thought guys just didnt like me,now i realise that the ones that ever did, before me getting close i push them away.Im sick of it cause im 17 and have never had a serious relationship.I get so scared about everything.I dont believe i can ever measure up to what a guy would want.Especialy with sex since i am so unexperienced and am not all that confident with being naked.The more i think of this,the more things i find so be negative over. Like one- My nipples are huge...this makes me beyond uncomfortable,is it weird? and does is turn guys off? I recently have been getting to know this guy and he seems lovely,hes a friend but i think he likes me as more.. the deal is that as soon as we'd get close id get really uncomfotable,causing me never to enjoy anything.Ive never even had a mind blowing kiss.I know im not a lesbian,Im highly attracted to males i just never connect with them well cause im so worried about how dissapointed theyll be with me.Im a size 12 and that also puts me down to,I may sound like some petty teenager but it a problem for me. So any advice or relation to this is very much appreciated :)

First of all, don't be so hard on yourself! There is always someone out there for every person who will appreciate you just how you are. Just be patient and wait for the right person to come along. Try doing something different with you appearance like a new hair cut or color, different make up and things like that can make you feel more confident. I think all girls feel more confident when they are looking their best! Just step it up a notch =) As far as the sex goes, if you feel uncomfortable that just means that you are not ready for that. You don't have to do anything you don't want to do, and when you're with the right person, I guarantee you will feel fine. I'm only 22, so it wasn't that long ago that I was in your shoes. Don't let what other people think worry you, if you meet a guy who you might like, give him a chance and don't be so worried about what other people say. One more thing, most guys I date are around 25 or older and they're still not mature or "mind blowing" kissers. Trust me. haha.