is this a fair behaviour?

hello. few persons know that im gay and i m pretty masculine so people dont get it easily. There are some girls that talk to me at university as they are "interested" and i like the fact that they are interested in me so i dont tell em that i am gay. i like being appreciated, even by girls. should i work on this or is it ok? i feel it is an egoistic behaviour. but i also think that these girls would treat me in a different way if they knew. i have no problem telling people i am gay, but this usually stops me from doing.