I have no background here, so take this for what it’s worth.
It doesn’t sound as though you’re writing about your sexual abuse. It sounds like you’re writing about how you’ve become a much stronger person-- a survivor who cares about others-- as a conscious choice because of that abuse.
At the end of the day, you’re not writing to get sympathy. The point of your essay is to show that you will be an asset to the college community.
I think that, written well, this could be an incredibly powerful essay. But remember: the emphasis is on you as a survivor, as a champion for others, and not as a victim. I think there should be a very quick mention of the reason you’re all those things. The maximum of those 600 or so words should be on the choices you’ve made since that time, not on the choices some psychopath made to abuse a child.