I know this isn't really kink related but

How can I make myself more open to sex? I'm super self concious and I always have sex with a shirt or hoodie on and we always do it missionary bc that's how I show the least ammount of skin. My bf however wants to try doggie style and eating me out and I'm sooo anxious. Should I just tell him we're never gonna do it? It sounds so embarrassing and scary, plus I've heard that with doggie style you can see everything. Please share any advice! (he's also mentioned boob jobs and that really has me worried cause my boobs are gross and the reason why I have sex with a shirt on)