Well I guess there's nothing wrong if you say or confess what you really feel for him but you must consider the consequence first before you do an action.
Let say he likes you too, now that will be the best thing to hear from him.
BUT what if he don't see you as a girl to be with, you know the "bf-gf thing" ? Would you risk your friendship just to clench your mind about what he really feel for you?
It's a hard decision to make because your putting the risk of the good relationship between the two of you right now.