Everyone heals and moves on at different times, you can't rush this process or else you will end up suppressing your feelings. Let yourself feel all the emotions, but keep them at a distance if possible, since it sounds like you don't wish to have feelings for them, then I would just keep busy and hopefully the feelings will subside. Best of Luck x
Getting rid of feelings is very difficult, there's no magic blue pill to just take to get rid of them. I suppose the main question is why you would want to? If its because they are a girl as well and people around you aren't accepting of that, or that you are already in a relationship with another person, whatever it is it might actually be easier to deal with that problem rather than trying to "lose feelings" for them.
In the end, time will tell. If its a brief, meaningless crush it will be over before you know it and if its more than that then its probably best you try to deal with the bigger problem that having feelings for this person is causing.
The way you feel won't change because you want it to, it doesn't work like that. It could possibly change over time, But if you strongly like this person, it won't. I think you should tell them. The feelings won't go away just like that, maybe until you tell this person it could...