hey b2l. i'm not an accepter, in the sense that i want rid of mine, but at risk of saying the obvious, it's about accepting yourself, period. you can choose to accept the gyne in the mirror or not, and you don't have to accept other people's stupidity with it.
for me the biggest step was just learning what this is, and maybe on some subconscious level, recognizing that this was not my fault, that it was nothing wrong with me or who i am, and that i had nothing to do with this. maybe it's just practice, but it would be the same way i would try to shrug it off if somebody was joking about where i was from, i'd think that was the most ridiculous thing i'd heard of. if you're trying to be social with people who are so insecure they have to act like that, are they really people you want anything to do with anyway? ask them if they make fun of disfigured kids in wheelchairs. tell them to get a life and stop acting like they were three. look them in the eye and ask them if they make jokes about people's ethnic physique or people with crossed eyes, ask them what's wrong with them. you don't have to be rude or hostile or pushy, you're trying to make them think and wake up. the main thing is you understand it has nothing to do with you, you keep peace with yourself, and you accept the fact that under the behavior there's a complete, good, sensitive human being down inside, but until they peel that off themselves, they're basically a bunch of annoying buzzing gnats. you hinted your family went to church. ask them if jesus made fun of the cripple at the pool of bethesda, and if not, whether he wouldn't throw them out of his temple as a bunch of loveless Godless hypocrites today with a good whipping. or get the reverend/priest/whatever to shame them for what they are (though many of those are useless cowards too). if that's not what's right, maybe something else will inspire you at the right moment.
the fact you're in the school age range makes it harder, because the fact is most of your peers just aren't mature. they're still testing each other for things to put down without thinking about it. for most of us, this was misery. taunting aside, it's wrong that a fit person should have to give up soccer or swimming, and the only thing you can do with what's already happened is grow from the experience and be glad you've found out what this is now instead of 20 years from now after scr*wing up the love of your life. i became an expert at changing in the locker room in seconds when nobody was looking. i've stated my belief here i actually think guys with gyne have a right to talk to a guidance counselor and get a complete exemption from pe just because it can be, even in the subtle ways, an unacceptably hostile environment, and if they want to make you sign a pledge to bike 20 miles a week, do it. if i had a kid with gyne, that's what i'd do. and if some coach were foolish enough to drop some comment about it to other kids, i'd threaten a suit and get his sorry @ss fired before the sun was down
your self confidence comes from within. it's got nothing to do with them. you're in control and decide what you do with this or not, and how you handle yourself. once they see you respect yourself, it'll be a little depressing for them instead or they'll have more reason to respect you because you're unfazed. if they still don't like you, put a friendly hand on their shoulder, smile, and tell them they're a sh*tty judge of character, you're a pretty okay guy, and they can go straight to hell