1st time having sex

Any tips/advice for someone who is ready to have sex for the first time but still gets nervous?

I know it’s all in my head but I get super self conscious about the way I look and I’m afraid that will change my SO’s point of view on me .. I’ve expressed these feelings towards him as we have discussed wanting to wait until I was ready.. this is the only thing holding me back .. and I don’t know how to combat this being in the back of my mind every time. Any suggestions ladies?