I'm a bad person if I "ignore" my friend's feelings towards me?

I'm a 17-year-old boy. I met this girl at school, and we've been best friends for three years now. From the first few months of our friendship, she had romantic feelings for me, and I know because she showed it to me and even explicitly told me once. I said I was sorry, that I was in a relationship, and that if she was okay with it, I'd continue our friendship, but some time I could still feel that she had some feeling for me. Five months ago, I broke up, and today my friend texted me that she loves me, that she doesn't want to ruin our friendship and our relationship, but that she wanted me to know, telling me she's sorry to leave me without a friend. So I asked if she wanted to end our friendship, and she said no, but that things wouldn't go back to the way they were. I texted her that it wasn't necessary; we'll do this the way we did the first time. But maybe I simply ignored her feelings and pretended nothing happened because I didn't want to ruin the friendship by not thinking about her. And now I'm doing the same thing again, would it be better to end this friendship? For me she's like a sister and I don't want to abandon our relationship but maybe it would be the best thing to do. ?