Dear NeedHelp:
I agree with Inky, above. If you do choose to express your feelings for her (and it may be a good idea as it may reduce the stress you experience wondering IF she will reciprocate), tell her in a casual way, not in a heavy-duty emotional way, but in a light hearted, no-big-deal way, with a smile. Then see her response and keep it light, whatever her response.
anita