Few questions about the military!?

I am stuck between the air force and the marines and i dont know which branch to join. Another thing is that i want to wait it out a bit im a senior in school and i want to wait a year or maybe two after i graduate to enlist. But My recruiter is telling me i should enlist now because this is the time of the year where i can pic a good job and have first pic on my top 3 jobs rather than if i apply late all the jobs will be taken up, and i dont really believe this.