Is this ok?

I am 40 year old step dad with a 19 year old step daughter. She goes to college and we have had her home only twice since last year. I never had any real feelings for her before but ever since past January my attitude has become a little more kind toward her. We talk more on the phone than before and she is more open to me than before.

Off lately I have noticed my longing for her. she has cute sexy feet and a very cute face. Even though she is on the fatter side, I still like her for her attributes I just described. She was home this past week and I couldnt help but sneak a few pics of her feet using my cellphone. I also noticed that she flashed her feet on me and her gorgeous rack. Also she does it very subtly and i have caught her deliberately changing her position when i arrive in the living room alone or otherwise. she knows that i like her feet and admire them, she lets me touch them too, but i want more.

what do u think I must do to handle this?