Me (M/18) and my online GF (F/18) of 3 years are trying to make our relationship more intimate. How would I be able to talk more intimately with her without making her uncomfortable?

For some context, me(M/18) and my gf(F/18) have been dating online for about 3 years with some meets irl inbetween. My girlfriend is religious and believes, atleast to my knowledge, no sexual intimacy before marriage. She's also made it clear that talk of intimacy such as sex make her uncomfortable. She is fine with suggestive jokes though, such as flirtatious remarks or talks about clothing. We talked with each other about trying to open up more and be more intimate, the problem is that both my gf and I are incredibly shy people. I both have no idea what to say in order to start these kinda things or even what to say, and she definitely doesn't by the fact she's socially awkward and has trouble defining her emotions. I so badly want to tell her everything that's in my head about her, but I can't. I haven't been able to for 3 years now. It gets exhausting somedays to feel these things and want to tell her, but all I can muster is an "I wanna kiss you" or "I wanna cuddle." I've told her about this and she agrees that she needs to open up more to this kinda stuff, but I still don't wanna make her uncomfortable.

So I guess what I'm asking is how do I ease into making my girlfriend more comfortable with talking more intimately/sexually? I know I need to say things that are probably vague and not too forward, but I can't think of anything at all!

TL;DR I wanna make my GF more comfortable with intimacy but have no idea how without making her uncomfortable.