Girls, is it really possible for her to feel this way?

So I met this girl and we instantly were attracted to each other. She gave me her number and we started texting almost everyday and then we started hanging out a school and on the weekends together. I asked her out and she said yes but we ended up just going to a party instead of going on a date. This whole time she had been flritng with me she still had strong feelings for her ex. She told me that I have all the qualities she looks for in a guy but she still likes her ex bf who is fat, ugly and doesn't take care of himself when I am the opposite. Can a girl in her situation still have feelings for an ex when she's found a guy who is practically perfect for her?