So I got into medical physics from doing research around my university. People think its hard to get into a lab but if you go and speak to a bunch of professors, one of them would love to have you because you are able to do their research for them and it makes their life easier. It is also really good if you join a program that pays you to do research. Every university has these programs, you just need to dig for them. When I entered college I knew I wanted to be in the medical field, but I didn't know what I wanted to do specifically. I've always like math and physics and while I was doing research I stumbled upon a bunch of papers on medical imaging and the like. I really liked it and I changed my major from biomedical to medical physics. I also like math and physics so the classes I have to take come to me faster and are more interesting to me. But finding a major you are interested in is super hard. If I remember I read a statistic that was "the average college student changes their major twice". Something that is also important is the job outlook. For example I like medical physics because it has a great outlook, the field is relatively new and there is still a lot we don't know.