Your HS in CA might have film production classes where you and the other students make digital shorts together. Or you can gather up some theater kiddos to act and photography kiddos to shoot and creative writing kiddos to write scripts and do it on the side.
For summer programs, use the search box in college confidential.
Here is one thread where I chimed in during the past
http://talk.collegeconfidential.com/summer-programs/1450979-summer-film-programs.html
Besides these programs, there are also smaller, inexpensive programs at Interlochen, Idllywild etc.
Good luck.