She sent me a message saying: (Don't be so nice to me, I will feel guilty, I don't deserve it) How can I reply to her? I like her, but ...

Or she just likes you, not to like you. She just doesn't want to make things difficult between the two sides. She should want to be more friends with you, maybe there will be opportunities in the future, but it is also possible that the opportunities are almost zero. She doesn't want to delay your youth, and she is afraid of losing your good friend. If you can pay for her without asking for anything in return, you can continue to be kind to her, but love is not moved. If one day you are moved by your love. I hope it will help you, remember that love needs feeling, and you will get the love you want even if you don't have to pay.