HELP! There is an older woman who says she has fallen in love with me but I am not interested, what to do?

I met a woman about a year ago. I am 20 years old she is 10 years older than me, I met her at school she was in one of my classes. I did not even know who she was before until one day she came up to me saying she needed a partner for a project that was assigned so I said okay because I didn't have a partner either and I didn't want to be rude and say no. After that I guess we just started talking and I didn't think much of it. But then she started to invite me for coffee or to go out witch was weird for me because she is older than me but I was like whatever. N-ways so one day we were out we went to dinner so then she started to open up too me about her past and what she has been through and I was like "why are you telling me all this I don't even know you that well" and she said she considered me a friend and I am not a mean guy so I guess I was okay. So one day we were out and she told me that she liked me as in more than a friend I said I was sorry but I only saw her as a friend but then she threw herself on me and kissed me I kind of pushed her of me and said I couldn't do that and it was weird so then I just took her home and she said she was sorry so I said it was okay so we stopped talking for a while because I felt awkward but then she would not stop calling me and she kept saying how she can't live on with out me ( witch I still don't understand how can you base if your going to live or not on one person) so I felt sorry and we saw each other again but again she threw herself on me and again I said no this was not acceptable. We kept on seeing each other because I wanted to be a good person because I felt that all she really needed was a friend because she seemed lost. But one day we did end up kissing and I sort of let it happen and we got intimate not actual sex but we did end up getting nude a snuggling although she did want me to fully take her but I said no I couldn't so we just snuggled and kissed ( witch now I totally regret because it ended up creating more problems for me) and now I feel like a jerk for letting this all happen I guess. Now I feel like a jerk because she still has feelings for me and she still says she wants to be with me even more but I don't see her as more than a friend I mean she is very attractive woman but I just don't see her being with me we live different lifestyles I am young and she is older. But now I do not know what is the best thing I can do because I want to be a good person I don't want to be a jerk or deuch although I feel like one. What can I do? I feel awkward around her now because she says she wants me and I feel I can't move on from this please help.