Is she keeping me as an option?

She said she’s really comfortable with me in a whispering kind of voice. We flirt occasionally, hold very deep eye contact, and have good chemistry. Every time she sees me she will shout my name, something she doesn’t do to other male friends. She also acts cold in some instances and I suspect it’s cause she still loves her ex. It’s like this girl wants to be my best friend but keeps me at a distance in texts (why do that to just a friend?). She doesn’t send me selfies or anything like that. We’re not even close friend I’ve known her for like 2 months. Why is she doing this? Keeping me on the back burner?
Is she keeping me as an option?
Post Opinion