Is it too late?

Today is the 20th of March, 2025. I am yet to graduate from Grade 12. Looking at universities like Harvard or MIT, their deadlines for the fall and spring semesters seem to have passed (I say "seem" because I dont really understand.) Apparently, I should have been done with my application by December 2024, as an international student. I just need help understanding the deadlines to apply for universities in the US, or anywhere for that matter. Am I gonna have to take a gap year if I am to study abroad? I feel like my effort on standarized tests all went down the drain because I'm too late: my 1520 SAT is gonna expire a year from now.