Your stats and EC’s look great, especially the ones that correlate with math if that’s what you want to major in. You can probably cut down on some EC’s on your app though since they’re a bit scattered. If you don’t have a leadership position in a minor EC, then you probably don’t want to put it on your app since it won’t help much.
I think state schools are the safes, and any school with an acceptance rate of 15% or higher should be a target. Northwestern is quite selective though (about a 10% acceptance rate), so it’s a reach. However, if you can craft your application well based on your math EC’s and shine in your essay, then you have a very good chance of getting in.
I’d appreciate it if you could chance me back! http://talk.qa.collegeconfidential.com/what-my-chances/2000649-chance-me-low-rank-common-ecs-cornell-harvard-wharton-etc.html#latest