I think that you are doing very well.
I like the fact that you are applying to safeties. We are not from Michigan. However, I think that your chances at U.Michigan are quite good.
I like your ECs also. I think that you should continue to participate and do well at the ECs that matter to you. As long as you are doing well in ECs that you care about, I would not worry about them at all.
It was by the way quantum physics that convinced me not to major in physics. I ended up as a math major.
Did you get 750 on the math subject SAT or on the math part of the normal SAT?