So from my experience, I don't personally know of any prosthetic programs that are started in undergraduate, the ones I have considered are all master degree programs. However, occupational therapy is a great start to being able to persue prosthetics down the line in a masters program. The two programs I have heard most recommended are at Eastern Michigan University and Northwestern in Illinois. However I'll add a link to all of the schools that have a program if you want to look into any others.
If you are considering going for a masters in prosthetics, I'd suggest looking at some of the requirements for the masters programs because some of the required classes may surprise you. (I'll submit some links below too for the schools I mentioned). But beyond that, if you're looking to practicing in prosthetics and orthotics I'd say to start volunteering at a clinic nearby. your home. Most of the time they will allow students of all ages to come and "shadow" or do observational rotations through their clinics. Free labor for them, they don't really turn it down. You can ask questions and help with patients, get advice and whatever you want. It doesn't hurt to send out an email or call and see if any clinc is willing to work with you and let you get volunteer experince.
Most of these schools really require a lot of volunteer hours to get in. Additionally, letters of recomendation from prosthetists, teachers, employers, etc are all things you should be getting written now so you'll have it just in case you apply later because grades are important, but those recommendations can certainly push you over the edge. Hopefully this all helps!
http://resident.ncope.org/prostudents/schools/ (List of all schools in USA that have certified prosthetic programs)
https://www.nupoc.northwestern.edu/education/masters-program/admissions.html (Northwestern Admissions requirements)
https://catalog.emich.edu/preview_program.php?catoid=30&poid=13085&returnto=5845 (Eastern Michigan admissions requirements)