The key is in give and take. You do something that's a bit more intimate than the last thing you did. Then you wait for her to match it or increase intimacy. If she never does then you go back to the last thing she did match.
She has to KNOW that things don't escalate without her participation.
The alternative is that you're the only one escalating and she's the "gatekeeper of intimacy" which is a dynamic where no one wins.
If you try this and it's clear her interest in intimacy is vastly different than yours over the long term, then you should assess whether this relationship fulfills other needs such that the lack of intimacy and sexual fulfillment is acceptable to you or if there are other ways of meeting that need that's acceptable to both of you.