Hello, Ansley R. - Your question shows that you already have foresight and are serious about becoming a theatre professional !
This question can be answered in general, however. You will have to decide where you want to live. The best opportunities are in New York City and Los Angeles. That would be for both technical and performing work.
Many people study in towns outside of the two cities . Many towns have excellent theatres that offer internships, a lot of times in the summer. I would say that it boils down to where you'd want to live. Definitely research various internship programs in various places. At the time I auditioned for an internship, I was told that I did not have as much experience as they require. Do build up credits and or experience . Audition for every school production as well as community productions. Build the resume .
The best opportunities will be discovered after you evaluate the various programs.
Michelle recommends the following next steps:
No matter where you go to school or where you live the best internships tend to come from Summer Stock: during the summer between semesters there's tons of seasonal opportunities. With this year as the exception due to Covid-19, typically there are theaters across the country that produce a season of shows and offer opportunities for paid or unpaid internships.
My other advice is that you can always request an unpaid internship: if you find a local organization or mentor that you can learn from, ask if they would be willing to accept you as an unpaid internship while you work elsewhere or attend school. Dedicating a few hours of a week to helping them and learning is a great way to get started if you don't have enough experience to secure a summer role.