Comfort Zone??

I always fantasize about having amazing makeout sessions with my S.O.  but like when the moment is right I always get super nervous and mess everything up and back out of it. He says we can wait until whenever I'm ready and there's no rush but like I feel like I am ready and I'm just nervous? Whenever the time comes i get racing thoughts and think about things like my mouth tasting bad and like poor lip placement and all the shit like that and then I get major hot flashes and feel like I'm going to pass out. Is this just a comfort zone thing? What should I do? I want to go have fun lol