Hey mate I'm an 18 year old also suffering with gyno and your feelings sound so similar to mine......though my story isn't really the same.
As you might have seen I got gyno in one nipple when i was around 12 or 13 can't really remember, went to a doctor and they said not to worry it would go away. See now this pisses me off, as I've heard if you catch gyno early and treat it, then it can go away. I've even gone to her lately and she's said the same thing, it shouldn't bother me and maybe it is here to stay but it doesn't matter........F$#k you too you ignorant doctor, it pissed me off so much. Just thinking that if she had treated it lately my life would be SO much easier, alot of the time I can't really think of any problems i have apart from gyno and a few body issues, I swear my life would be so incredibly good if I had a good body like so many of my friends.
I'm not THAT self concious about taking my shirt off with gyno because I can pinch my nips and they go hard, but I had to box someone once and everyone was so curious to why I kept rubbing my nips hard. I made an excuse but I couldn't do that every time. It's not so bad swimming because you can do it discreetly.
Anyway I'm rambling and just want you to know I feel pretty much the same way as you. It hasn't ruined my life because I still have good times, but it affects almost everything I do and makes me incredibly self concious. I could dress so much better and live such a hassle free life without gyno.
Oh, and with the girls, once you've lost weight you might have the gyno to the point of where it wont show through black shirts at least (black is slimming) and they will start coming. Don't worry too much about having sex first time, chances are you'll be in the dark or under covers so she wont be able to see. I guess after that you can keep pinching your nips but I reckon that's pretty shitty and I'm gonna have to deal with it soon. See most of the times I've had sex have been either with her not looking or under covers. I'll think of something. Right now I'm hoping for andractim to work. Even a slight change would be worth the money. And dont worry about being a virgin, I'm not an old fart who just says that because they dont understand, I'm 18 and just finished school, I know what the whole virgin thing is, but everyone gets over it so quick, my school went through that stage but by the time I was 18 no one cared in the slightest.
Anyway take care dude, I'll be here to talk anytime you feel like it. Keep up the struggle, life can be good with this, especially if you lose weight and feel better about yourself, unless you're already happy with your weight I couldn't tell from your post. I've kinda got stretch marks on my hips from when I put on weight but I guess they're not too bad and can be passed for scars. ANYWAY just letting you know you're not alone with this.