Arguments so i can join the reserve at 17, i need my dad to sign...?

i would really like to join the marine corps reserve at 17, the positives outweigh the negatives. its like a job, i get paid, i get credited with time and experience, and i enlist at pfc or l.cpl. problem is, my dad doesn't want to sign the paper. his reasons were that i am not "military material". any successful arguments for this? also he would rather have me be commisioned as an officer, but i want to do time as enlisted before i do MECEP. btw i have been in cap (civil air patrol), for two years, c/ssgt.