I'm going to sleep with an ex's roommate
Is she interested in you?
I think she is.
Even though she is attracted to you, you should not sleep with your ex's roommate. It could create problems with their apartment that can spill over to you.
I don't think it's that serious just yet.
It may not be serious now, but it can turn that way quickly. I think you should find someone else that is interested in you.