Respect comes from being upfront and honest. Respect her enough to be honest with her about what you want. It’s how you handle it AFTERWARDS that is the biggest thing.
Ask her to go down on you or ask her why she doesn’t seem to want to go down on you. Direct it on yourself, “I feel” “it makes me feel” “I could be totally wrong…” etc. Just don’t accuse her of something. Tell her how you’re perceiving the situation, which is that you think she’s uncomfortable with it.
Then you’re going to have a conversation about it. If she feels uncomfortable, respect that, and try to get her to explain why, and you guys can try to work on it. Maybe she doesn’t even realize that you feel like you’re not getting enough of it in return! Maybe you’ve been so obliging in the beginning because she was a virgin that she now thinks you DON’T want it as much as she does. We don’t know what goes on in other people’s heads! We can guess all we want, but the best chance we have is to just ASK THEM. Hopefully they’ll be honest with you in return.
It’s a conversation you need to have. You can’t try subliminal messaging to make her want to lick your pussy or bend over in front of her face and wag your ass to say “EAT IT!”. It’s the equivalent of a guy trying to push a girl’s head down to suck his dick. It’s insulting and not at all subtle.
Just talk it out.