I am interested in an older women, she seems somewhat interested to. How do I know for sure?

I like this girl, Im 19 she's 22. She knows I like her, and say's we'll see which seems to me she's not closed to the option. We talk almost everyday for hours. She lives in LA I live in northern Cali so we talk mostly on IM, and whenever I get online she talks to me right off without fail and asks me about my day. She flirts aswell, Id say something like "Ill you" and she said "you wouldnt dare ;)" this seems to be flirtatious right? And when saying goodnight she says "goodnight love." How do I kow for sure if she's interested without full out asking her, she's a fantastic beautiful women, would hate to do anything to scare her off.