You will be happy at any of the following schools in regards to your skiing experience.
UCSB, UCLA, USC, CPP/CP, UCSD, SDSU, CSULB
I have also recently heard CSUF and CSUN
They all belong to the SCCSC or have access to other schools teams... This means they have around 10 weekends of competitions in Mammoth with huge trips done pretty cheap. The competitions include halfpipe, slopestyle, skiercross, slalom, and GS. No one gets too serious and burritos have been in hand during competitions and so forth.
But on top of that, with So Cal, it's 1 - 2 hours to Mt. High and Big Bear which is kinda like going to a playground. I used to go in the mornings before my 1pm classes. It would be like going to Echo from Boulder for a few fun laps only the parks at both are pretty amazing.
Season pass to Mt. High, $300. Student season pass to Mammoth/June $300. Season pass to Mt. Baldy $50 (sometimes they do this). You will think you will make it to tahoe enough to buy an Epic pass, but you will likely not unless you plan some trips to CO.
That being said, instate tuition at one of the UC's is around 10k a year. To CPP, CP or a CSU it's around 4k a year. USC.... 30k a year.
Out of the list I gave (less USC), the easiest access to the mountains is by UCLA, CPP, CSULB, CSUF and CSUN. Cal Poly and UCSB are about 6 hours to Mammoth, but they still shred hard. UCSD and SDSU are 3 hours to mt high, 6.5 to Mammoth.
Yes, it's 4.5 - 5 hours from LA to Mammoth, but this is no exaggeration when I say I have friends who live in town and go to school in LA. I did it myself. All T/TH classes and would skip T or Th every other week.