Attraction to coworker 6 years older than me

So basically I've kinda had somewhat of a crush on a friend or "coworker" of mine who's abit older than me as she's like 26 or something keep in mind I'm 20. I noticed that over the year and a half span we've definitely gotten to know each other pretty well as we are usually pretty social around each other at work. We usually end up taking breaks at the same time almost everyday intentionally and unintentionally, regardless I always have a good time hanging out and talking to her as we share some interest and she often tells me about when she was my age (which really wasn't that long ago). I really get this vibe off of her that she can relate to me as a person, Sometimes it seems she can get kinda flirty with me especially when she can tell I'm really stoned. What got me thinking one time was when she mentioned one of my coworkers who is relatively the same age as I am trying to flirt with her and she shot him down, she also told me "not to be next" in a way that was pretty sarcastic. What I noticed about this is that I flirt with her often and she will often flirt right back but never seems to want to act out on it. and I'm not sure if this is due to the fact it may make her look bad or if it's just that she feels comfortable around me. it sucks because I think she's really cool and would love to really get to know her outside of the workplace regardless of what year we were both born. I honestly just have no idea about how to tell her how I feel about her as I just don't really see a way to go about telling her.