Worried about sleeping with someone else

I was with my ex for a few years. He took my virginity and is the only guy I’ve ever slept with. We broke up in march and recently ive been talking to this new guy. I’m very comfortable with him and we’ve already done some stuff, but we haven’t actually had sex yet. But I know it’s gonna happen soon. I’m scared. Not because I don’t want to or because I don’t trust him, I do. It’s bc I’ve never been with another guy and I’m scared I won’t be good enough for him or he won’t find my body attractive. I’m currently trying to lose weight and I’m very insecure about how my body looks. My ex is the only man to ever see me like that. I’m so worried that I won’t be good enough because he’s been with a few more people than me or that he’ll see all of my body and be turned off. I doubt it’s gonna happen but I can’t stop my anxiety. How do I calm myself down over this? Is this even something I should be worried about?