<human>: Needed some solid advice on this..

I fell in love with a girl I've known as family friends since childhood, probably age 10 or 11 around the start of it (we're the same age). Since that time we only spoke briefly each week at church but mostly just waved at each other (where we were also introduced to each other's families back then), or when she would meet up with my older sis a lot (who's still close with her). We also attended many parties together but nothing beyond friendliness in all cases. Me and her never really had feelings for each other initially BUT I was only slightly told she had a big thing for me back when we were young but never came to fruition and I never heeded any signs either, although I asked some of our mutual friend circles and all of her female friends told me she doesn't have a thing for guys right now because she's too focused on academics. 

Fast forward to this year, she got accepted to a top level grad school and her family is actually moving out of state for business as well so she will be departing the scene soon. I feel that I am losing touch with her as we start to go our own ways after this.

My question is, should I confess the truth to her after all these years of our friendship? Should I tell her how I feel about her before she leaves or should I drop it all entirely and abandon ship anyway? My brain tells me to consider the risk of her friendship going the wrong way but my heart tells me to tell her how much she has meant to me all these long years of patience. My sister informed me that being an attractive guy who works on himself years from now will prove to my crush that I will be the man for her in her future, although not sure how long that will take.

Can you give me a shortened version of the text?
<bot>: childhood crush is moving away for long time, need help on whether to confess my feelings for her after many years of friendship or leave it as be in hopes of her reaching out to me down the road.