You could pull up your math SAT if you are able to take it again. I’m not sure that being the president of a gamer club is much of an EC but I’m an old fogy so feel free to ignore that comment. Your story is compelling and your stats generally put you in the mix. Dartmouth is a reach but it’s a reach for almost everyone who applies. You’re unique enough that it might be a near reach, but none of us really knows what the admissions folks are looking for these days (or how how much the need for aid will factor in). Is the cross country coach aware of you? I would reach out and make contact if you haven’t already. Sometimes you just need one little extra point.