Yes but you have to be realistic if she's just not interested in you, it's not going to go any further so you have to move on and look for other people. If you are just hanging on and hoping that "something will change" then you are kidding yourself.
The exception is if you sense some chemistry between the two of you but the current circumstances prevent you getting together, eg one/both of you have a partner, you live in different places or whatever. Circumstances can change and you can get with a friend, sometimes a long time friend, in the future.