GH - One of the things I remember well from dating and being with my wife that was very consistent woman to woman is the "lingering in your embrace" time - it was a good indicator of how far they might want to go at that time. A couple other things - speak very softly, but in a mature voice, to see if it draws her closer. Also, see if she moves her body under your hands - if she's very still, it's an indicator she doesn't want to go further.
I don't mean these to be "tricks", just a way of checking the water before jumping in - you're right to go slow, even though it's hard [difficult a better term? ].

Writing this is tough - you can imagine what I'm thinking....