If your "friends" make fun of your penis to the point that it makes you want to have surgery to make it bigger, then they are not friends worth having.
As for the anal sex, how selfish can you get? Do it so that you can give the love of your life very strong orgasms. Not every time you make love. Once in fifty is about right. Do anal sex for her. Not for you, if you don't like it.
Oh yes, romance is FAR more important than penis size - to anyone with their head screwed on properly.
Penis size matters far more for you than it does for any woman worth having as your girlfriend. If you want to have penis enlargement surgery, that's up to you. Don't expect to become a sex demi-god just because you've had an operation to make it bigger.
With sex, it's what you do, how you do it, and for how long that counts for far more than the size of your tackle.
How do you think lesbians manage to have deeply fulfilling sex?
Most men would make much better lovers if they made love like a lesbian.
Some women prefer men with larger penises. Some women (especially those into anal) prefer men with smaller penises. Most are not too bothered one way or the other - not too the point of dumping someone because they're too big or too small.
Real life is not like some porno movie where the actresses drool over well hung men.
...And what is the length of your penis when erect as measured along the top of your penis. And what's the diameter?