Where do we go from here!

Whenever I [27M] try to talk about sex with my [26F] girlfriend in any real meaningful capacity she says she’s worried that I don’t enjoy sex with her and that she’s not good enough. She says she isn’t vocal and doesn’t think she’ll ever be when it comes to sex, and she needs me to take the lead on this sort of thing but then gets nervous and stressed when I do because she thinks I’m not satisfied. I’ve reassured her that isn’t the case at all and I’ve tried my best to explain my intentions and even just say I want to know what she likes but every time I do it ends up with the same response.

I’m at a point now where I’m really not sure what I can say or do going forward, I think sex is importantly in any relationship and communicating about sex especially, how am I supposed to know what she likes if she won’t tell me? For reference we’ve been together 10 years and we are each others only sexual partner and gf/bf in general.