It can be very overwhelming! My advice is to take all the schools you’re interested in and make a spreadsheet of their pre-reqs. You can’t take every pre-req for every school, but you can eliminate some schools and take pre-reqs that will work for a bunch of schools. My spreadsheet probably had about 20 schools, and I applied to less than 10. Maybe take some classes over the summer or after you graduate at a cheaper, local school if you can’t fit them all in during your undergrad. Does that help? Do you have other questions?