You seem to want to make a decision and stick with it. Or, at least you seem to want to be confident that you know where things are headed.
She's a go-with-the-flow type who likes to see where things go day by day. She may not have been as seriously into the relationship, at that moment in time, as she sensed you were, or wanted to be. Eventually she knew she couldn't or wasn't willing to give you what you needed to be comfortable, so she agreed it would be best to part ways.
I can't get emotionally involved with someone, decide it's not going to work, and then go back to the way things used to be. Because at that point, things are already not the way they used to be. Or maybe you could between two thinking types. But it's never worked out for me.
Personally, I'd prefer to have a relationship with someone I was close friends with first. But I'd have to be pretty certain we were compatible before moving on, because I'd hate to spoil a good friendship.
My relationships are constantly evolving, but I usually have no idea where they're going to end up. Once I develop an emotional closeness to someone, I can't take that back, only hide it to protect myself.