I've been there, my friend. Best thing you ever did was tell your dad. You've laid the groundwork for years to come. I wouldn't recommend surgery right away (listen to yoru dad for now). But, you may want to consider it in a few years. Whatever you do, if it bothers you for years to come, the more life goes on, the more you'll wish you would have taken care of it earlier in life.
I agree, it's very good that you have your dads support here. Don't do like me, and probably many others, and keep your problems to yourself. It will just build up and cause morbid thoughts... I would also recommend talking to a psychologist. I don't know if you feel you need it but I think that at your age a professional could be of great help. It's not just about living with it, but it's also about not letting it hold you back. Too many people already spend their lives in fear and anxiety, don't become like that.
Off the top of my head I would also like to offer another piece of valuable advice. One important aspect in kids social lives, aside from not holding back and actually learning valuable social skills, is... well, fashion. Now you should not misunderstand this. I'm not suggesting you start dressing to "fit in" or anything stupid like that, and i'm also not suggesting you should freak out and "express yourself". However, one big problem for us guys with gynecomastia is, obviously, clothing. Of course this gets harder the more gyne you have. Also alot of us have probably made some really bad choices regarding clothing, at some point or another.
Now here's the deal; we can all apply our minds to this and make wise choices(or atleast less bad, if want to look at it that way). So, learn a little bit about fashion and clothing, and find out what works for you. Loose clothes is not always the best way to go either. If you dress intelligently you will not only make the gyne less apparent but clothes can also project confidence and a good sense of taste.
I can give you a concrete example from my own experiences. When I was younger I always dressed in very loose fitting clothes, thinking it would hide my gyne. Later I have realized it probably made things worse. Nowadays i'm much more well dressed. I might look terrible in a tight t-shirt, but with a well fitted shirt over it it's a completely different story. Combined with a jacket or something on top of it I can be pretty comfortable with the way I look. This is just from putting on a few layers of clothes, which fit very well. Darker colors can help very well too.
This is just an example of what works well for me, and probably many others too. It's not necessarily the right way for you, that's something you need to find out for yourself. Just put a little money and effort into it and I think you can make things a lot easier.