There really should be a plan not only at the school but also between your parents and you. Are they involved in your preparation considerations? They should be. Ask them to talk to the principal and ask about the school's disaster plans.
Most schools in my area plan on keeping the kids at school after an earthquake. Schools are fairly well set up for this, by the way - restrooms, cafeterias, and maybe a gym for everyone to gather in.
If a quake happens while you're at school, your parents need to have a plan on how to get in touch with you (don't count on phones; maybe FRS in short range?) and where to meet you (if the school will allow you off campus).
By the way, see
http://www.cityofsanmateo.org/dept/oes/firstaid/index.htmltheir list of supplies for the home and for children.
Take a look at these links concerning go bags:
http://www.city.vancouver.bc.ca/corpsvcs/emerg/ess/grabngo.htmhttp://www.coquitlam.ca/Residents/Public...+Checklist+.htmhttp://www.chilliwack.com/main/attachments/files/346/Emergency_Grab_and_Go_Bag.pdfhttp://lifehacker.com/software/screenshot-tour/show-us-your-go-bag-part-2-292427.phpSome of these links tell about what to have at the office or work place - this is your school, so use that information. I also suggest a deck of cards or some other game to while away the time, earplugs, a towel (read The Hitchhiker's Guide to the Galaxy), and a nice, long book (maybe the Hitchhiker's Guide to the Galaxy series).
I' say, though, that the most important thing is to have your parents and you understand what the school's plan is and to have a plan for getting to you after the big one.