Your sexual anxiety and fears around your size are going to do more harm to your relationship than your size. You sound absolutely average, meaning you are in the realm of where most men are.

Comparing yourself is never good, especially to those in porn.
I am a woman, and I can tell you right now, if I compared myself to the women in porn, I would never measure up. I'd be crying myself to sleep each night.

I'm older now, but when I was younger, my breasts were always on the small side.
There are women who don't feel their vaginas are esthically pleasing.
So you're not alone in feeling you don't measure up. These thoughts are just that. Thoughts. You can give them credence or tell them to f off.

The bottom line is we are all perfect in our own ways. Just our minds like to tell us we're not.