Am I stuck? (Choosing an MOS)?

I'm trying to get my parents to sign for me to be in the 14 month DEP for the army this april. Unfortunately my recruiter mentioned that I wouldn't have much time to go to school with an MOS in combat arms. My primary choices are 13B or 31B. And I kinda have a feeling that if I say I'm picking one of those jobs they won't sign. I could always wait, but wouldn't get any DEP benefits. My non-combat choices would have to be 92A, and 25B. Either or with an Option 40. But still, I truly want to earn my freedoms and privileges. I also can't seem to get it through into my parents mind that I don't want to be in a clroom setting for another 4+ years. I feel its my time to serve, and I can't stomach being a bystander much longer.