I think it's time to tell her everything too, since she has already made several observations.
If you start the conversation then you can direct the flow of information. She may be operating under some false assumptions, especially if her past CDing boyfriend abused her trust or violated her boundaries.
She needs to know that just because someone engages in cross-gender expression does not mean they will take advantage of someone else, and when two people are in a caring relationship, the rules of engagement can be negotiated without either partner needing to fundamentally alter who they are.
And if after your talk she is not willing to take it any further, then it is best that you know this sooner than later, IMO.
Good luck!
