Does class ranking matter if the school is small for T20s.

Sure you can apply. But it is going to be anywhere from a reach to a very high reach. Do 10% of students get into top colleges from your school? What is causing you to be at the 10% mark? The top 10% of all HS students is 390,000 students. The number of students that attend t20 colleges is 40,000. What puts you in the 40k and not the 350k?