As far as I’m concerned, there are two types of pseudo-relationships you can be in that aren’t real, bonafide relationships: You’re either “hooking up” (casual booty calls, probably not going anywhere) or you’re “dating” (going on dates, getting to know each other, hopefully going somewhere).
She is free to spend time with whomever she wants and can choose to be intimate with whomever she wants. The freedom to have alone time to counter the stress of being busy may be the reason she's only been interested in an ambiguous relationship up to this point and not a committed one.
Of course, life has a cute, charming way of making things unnecessarily complicated, so there are about one million different stages you can undergo within the “hooking up” and “dating” stages.
But overall, odds are you’re doing something that falls under one of the two umbrellas.
I say we were “dating” in the beginning because we were regularly going on dates right off the bat.
They started off as casual, and then things got a little more serious when we became exclusive.