Hi and welcome to the forum!
You could not have found a better place for help!
Having said that though I encourage you to check everything that has been presented to you here with a professional in order to make sure it is appropriate for you.
I was like you at your age...until recently I found out that the best thing you could do for yourself is to exercise your WHOLE body. Not just the pecks but every darn muscles that you got! Doing this while having a clean diet will get rid of these man boobs you refer to.
Also, if you have low self esteem, then I encourage you to go to the gym and desensitize yourself to this. You might think that you will find a bunch of ego-inflated iron-pumping goons in there, but it isn't the case. Everyone is there to work. *IF* someone is trying to ridicule you in anyway, ignore them and keep working, you will have the last laugh my friend, while they are laughing their butts off you will be walking the walk and getting closer to your goals and that's what it's all about.
If you want a little direction, here it is:
- Introduce yourself to proper nutrition.
- Introduce yourself to proper workout program development.
- Grab the above, use it and reap what you sow.
PM me if you need some more help man!
Good luck!
Eric