What kind of hair dye should I use?

I'm 13 and I have dirty blond/ light brown hair and next week I want to dye streaks in my hair maby pink or red also my hair is shoulder length, the thing is my school dosnt allow dyed hair so I want it to last maby a mouth because I'm going to camp after that what. kind of dye could I use that would be out in a month and don't want it to wash out in water because I go swimming about once a week