if i've heard correctly once you are sixteen you can apply to be a cast member, but you are limited to the positions that are available. for example, you must be 18 to work in op's (attraction, trans., front gates, ect.)
so i would say go for it and good luck.
other options could be, quick servive food & beverage, full service f&b, custodial, merchindising, hotel hospitality, and there are probably others that i just can't think of right now.