Oregon has a minor in global health. Not sure you need to major in public health to get an MPH? If she likes UO as a school, you might look into that.
As you’ve already learned, at 17, they really don’t know what they want. My kid changed four times in his last two years of hs and most kids change majors in college.
If she wants OSU, why transfer? It seems as if you can still apply, per the website.
Good luck.