How long do think ill get on probation?

in february i got an mip for drinking, i got on derverion. they told me that it would be off my record because i was on derverion, but i can't have any police contact until im 18 then it will be off my record. so i thought yeh i just got to be sneaky. so two week me and friend were on school grounds outside on recess and we were smoking out of my pipe. everything was fine. then the next day-friday me and the same friend and my other friend decided to do it again. this time we got caught. the teacher only thinking it was cigarettes, but the princel found a pipe and some bud. what do you think my charges will be? fact:not a crack pipe.. my mom thinks i should go to rehab for this, and my the courts wont be so hard. i think she is crazy, what do you think?