Well, I'd start by exploring with my hands (to the point of fingering if she's comfortable) and see where it goes.
Is she telling you she's not ready? If she's ready to have sex, then I'd go for it. Of course, start with whatever you want. I guess hands-mouth-genitals is a natural progression.
Even if she is a virgin she will still know what she wants. Don't discredit her because you are more experienced!!
Although I think it's really great and responsible for you to be so concerned about her pleasure and readiness....