Coming from TJ, your app looks pretty solid. Your SAT verbal is a bit low for what I would expect from a TJ student (is English not your first language?), but your stellar math score makes up for it.
My question is, why NSU? Why not go to UVA with everybody else from TJ? I know the competition from within TJ and the other top northern VA students is tough, but there's no reason you couldn't go to a much better undergrad than NSU (don't hate on me here, it's true).
But if you really want to do a dual program, your chances for NSU are great-my only suggestion is beef up your shadowing experience. I'd also suggest looking into the other programs out there:
http://services.aamc.org/currdir/section3/degree2.cfm?data=yes&program=bsmd
I know PCOM has a dual degree program as well, but I'm not too familiar with what the other DO schools offer.
And my last bit-o-advice: take stats. It'll be way more useful, and you're clearly talented at math so it'll be easy.