It’s what you make of it.
It is hard to deal with rejection, but you reject women as well. There are women you don’t even notice because they don’t fit what you are looking for sexually. (Too old, too fat, too masculine, bad teeth, whatever.) Women aren’t all that different. So if you get with a girl, give her the chance to see what she thinks. Don’t decide for her. If she’s not interested, fuck her. There are lots of other girls out there, and for many of them, your penis size is down near the bottom of her priorities.
Work on your size if it makes you feel better. That’s why you’re here. But more importantly work on your confidence, your sense of humor, the way you treat a woman to make her feel good about herself, your love making skills like kissing, foreplay, oral and manual, stamina, etc. There is a lot you can do without PE to make yourself a guy girls would like to fight for. With PE, its up to you how much you want to work, but do it for you, not for some imagined woman you haven’t met yet who you fear might disapprove.