Is it normal that i'm a straight 21 y/o that is extremely shy about sex

Okay, so I'm pretty shy. I used to be very outgoing, but once I reached an age where boys started to become a big thing (like around 14 or 15), I have just been so shut off from them. I get nervous when I'm around them, I've never had a boyfriend, and people are starting to think I'm a lesbian (I'm not a lesbian- I find girls extremely attractive, but I have no desire to be sexually active with a girl).

A huge thing- when people bring up sex, I get so nervous and flustered. I love sex, though! I masturbate daily, and I'm into some kinky stuff. Even writing this post is giving me anxiety. So, I guess what I'm trying to ask is how do I become more comfortable with my thoughts on sex? I seriously get so flustered whenever it's brought up and I blush and I really just hate it. I want to learn to be comfortable with talking to other people about it, and I want to be able to have sex with a guy without it scaring the shit out of me (I'm kind of scared of guys, but I'm straight. It's weird, I know).

Also, I don't know if this has to do with anything, but I don't have any men in my family. So do you all think that has to do with my ~fear~ of men?