Does your friend know that you like her? I'd never do that to a friend but maybe you guys aren't that close. Anyways, you should definitely go for it. Don't be one of those guys who's waiting around while the girl you really like is being taken out by somebody she might not even like as much. Go for it!
-to be nobody but yourself in a world which is doing its best, night and day, to make you everybody else means to fight the hardest battle which any human being can fight; and never stop fighting.- e.e.cummings