The are no right or wrong answers here - you can’t go wrong with either choice; everything depends on you and your family’s unique situation.
@hackeysack has given some of the criteria for you to consider – 1) your family’s budget for undergrad and what they will are or are not comfortably able or willing to spend; 2) what their abilities / plans, if any, for contributing to grad or medical school are; 3) whether or not you have siblings; 4) what is important for you to have in your undergraduate experience.
If indeed money is a big consideration and are do end up in med school, certainly saving the money now would probably be a good plan.
USC is a big school, but it’s fairly compact and programs like TO and FSH will make it seem smaller.
My D turned town a Trustee’s full-tuition at USC (she had other full tuition merit at schools she like more than USC, so it was a non-issue). She’s now at Stanford. That said, she’s an only child and is in a humanities field where one’s undergraduate school and mentorship will probably matter for grad school than it would for med school.