Do JROTC for four years in highschool and then when you're done go to some military college to become an officer.
I think what you're looking for is college ROTC. That only puts you in as a higher ranked enlist. OCS and GREEN TO GOLD and something else is what gets you in as an officer.
Remember, the higher rank you are, the more danger and more responsibilities you have. A Colonel is in charge of 3,000–5,000 men. A platoon leader (Second Lieutenant) holds the lives of 26–55 men in his hands, and he is leading from the front, where all the bullets and haze is.
It takes something of a man to do this job.