Massachusetts Private High Schools

I’m in the eighth grade and I’ll be applying to St Mark’s School, Concord Academy, Worcester Academy and Dana Hall aa a day students. I was hoping to hear about the grades and ssat scores that the admitted students of each school have. I’m studying for the SSATs right now, so I don’t know my score yet. In sixth grade I only had one B+ and all the rest were A’s. In seventh grade, I had 4 B+'s 2 of which were in math and 2 of which were in Spanish. I was in an advanced math class.My school does trimesters. My school only offers advanced science and math courses and I am in the advanced courses of both subjects. What do you think my chances are at each school?