Is she flirting with me?

There is a woman at the gym that I think is flirting with me. She is about my age and really in great shape. I hardly ever talk to anyone there, I go there to workout, not to meet women. If I am doing cardio on an elliptical machine I have noticed that she has been using the machine next to me. Today I was working out on the bike and she got on the bike that was next to me and the other 5 bikes were not being used.

Sometimes she smiles at me.

Updates
6 mo
there is a training room that i use on a regular basis. It has squat racks, some sleds, K-straps and other equipment. I workout there after I do cardio. last week she has been showing up in that room. I have never seen her there before, Am I just imagining this?
Updates
4 mo
I was sick for a while and did not workout for 3 weeks. When I got back I noticed that this woman was not there anymore. after a few weeks I figured that she was gone. Last Friday i am pulling into the parking lot. A car suddenly pulls in next to my truck and it is her. I just said good morning to her and ask her how her workouts were going. She tells me she has been using the pool because she is training for a triathlon.
Is she flirting with me?
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