Too ashamed to have sex?

I’m 18 and in college and I’m finally ready to explore sexual things. However, I’ve had a bad relationship with my body since I was young and I’ll always put myself down for the smallest things. I’m scared to have sex with someone, thinking they would see all the awful things I have been seeing all these years. I’ve recently been talking to this girl but I’m scared to be in a relationship with her because with a relationship, comes sex. I don’t know how to get comfortable enough with my body to be intimate with anyone yet. But I really want to be! Any advice?