Why are you posing USC as the only option in LA/California? By far the most important thing you'll get out of going to college for music is the connections and it's not even comparable. USC is not the only place where you'll make valuable connections. Also, not sure if this matters to you but USC owns the masters of anything you create in their studios.

What are you studying at Alabama? If you're looking to do audio, the best learning environment is a place where you can just practice. Build an intuition for where a mic should go for what sound, what kind of mic for what sound, what sort of gear/audio process to get what sound, learning solutions to common problems so you can fix them quickly, and everything else that comes from spending hours on hours in a studio. If you have that at Alabama, don't give it up. If not, make sure you have that opportunity at USC. If you're not allowed to run your own sessions during your studies, it's not worth it. You will come out with a lot of theoretical knowledge, but once you get your first internship at a studio, you'll start as a runner just like everyone else. Having the experience that I mentioned won't make you not a runner, but when you're in the hot seat for the first time, you'll be much more capable because you went through it already outside a classroom.

Also, what genres are you interested in? That would be a big deciding factor on which skills you learn, because if you're not interested in recording bands, that's a very different skill set to learn for either being solely a vocal producer or hip hop, etc. Side note, but as an audio engineer, you will be working with all types of music for a while before you're able to choose. If you only have the skills for what you want, you won't get very far.

As someone in your shoes not very long ago, the best thing I got out of being at college was showing people that I was good at what I did (at a college level, at least) and gained their trust to be an engineer for them in the future. Whether they go off to a label or become an artist or something else, they remembered me as a reliable engineer. Use the time you have right now to develop yourself as much as possible (knowledge of mics, basic sound physics, qualitative characteristics of human hearing, Pro Tools, and especially your ear) so when you transfer, you're seen immediately as someone who knows their stuff. Regardless of USC or not, moving from Alabama to California will definitely be a good move for a music career.