Well you're entitled to have feelings for her - those feelings don't necessarily have to become action. To be honest it doesn't really sound like the most opportune time for you to begin a relationship - you've just started college and have bigger priorities than working through your sexuality AND a new relationship with someone. Also, i hate to be devil's advocate but there's no guarantee she'd be interested in you anyway. Such a rejection would be difficult to contend with when you're also entering a new and important phase in life.

The fact that you've liked her for so long does suggest that your feelings could well become more and should everything fall into place - you could possibly make a go of it. As it stands, she's four states away, has just broken up with someone, and you're both now involved in higher education. Timing is everything and there are risks either way (i mean if you don't tell her she could well move on with someone else) but for the moment, i think the risk of rejection is greater than simply not knowing.

Maybe play it by ear - once you've both settled in to your new routine and she's had time to grieve her last relationship, perhaps test the water. But you must be prepared for the difficulties of long distance relationships if things go ahead - as well as the trust issues that arise from not knowing what your girlfriend is up to most of the time.

It's your call but for now i would play it safe - if it's meant to be, it'll happen some day.