Getting an associate degree or going straight to the army?

hello guys ive graduated high school and began thinking about what to do with my life my plan was to enlist in the united states army and become an mp i planed to enlist in august now heres the dilemma my cousin was a 92a and my brother is a current 0331 lance corporal they have told me go to school and at least get your associate degree. any help would be appreciated and why do u think they say this thanks they tell me i don't know what its really like its not like the commercials they show