I agree with dropping the labels. Honestly, it seems more people here get all screwed up and wacky about where they fall within some arbitrary hierarchical structure - primary, secondary, etc. None of that means anything, it's how you treat each other that counts. I read PolyNrrdgrrl's introduction
and she is questioning that hierarchical viewpoint now, which I think is good.
As for "how her other relationships will effect ours, how often we see each other, or how she feels about me," those are things you need to discuss with her and see if there are any boundaries you might ask for. She doesn't have to be the only one setting the parameters. And you are worrying about things that aren't happening yet. Take one step at a time. All you two need to do is keep communicating and handle each stage of the relationship as it comes along. Stop projecting into the future, which could be radically different than anything you imagine. Besides, we always tend to imagine the worst-case scenario. The future could be great, too, you know!