Applying REA Stanford without subject tests (accidentally took wrong test)

I agree with your guidance counselor. If your ECs and academic awards are as outstanding as you claim, I think they will outweigh the subject II tests. For students reasonably good in math, the Math 2 test is fairly easy. I am sure the admissions officers know this.

Also keep in mind any opinions you get on a message board are guesses at best about what the admissions officer is thinking. Good luck.