Commissioning is something that happens after you have completed your degree and are graduating. If you complete all the ROTC requirements, have your professors sign off at the end of your last semester of your senior year, you will commission usually the day before your graduation.
You are not commissioned during your time at college and ROTC, the scholarship is something different. Since you did not receive a scholarship prior to starting school, you will now be able to compete for any Battalion scholarship the battalion might have available. It is possible to receive a scholarship from the battalion anytime during your time in ROTC. These can be a full 4 year, 3.5 yr., 3 yr., 2 yr. You would be competing with all other non scholarship cadets for one of these scholarship so make sure you do very well in both ROTC and Academics as soon as you start school. There is no guarantees your Battalion will have any scholarships available, this can change from year to year, just make sure you keep yourself as competitive as you can.
If you do not receive a scholarship at any time you're in ROTC you will need to be recommended by the PMS to continue on to the Advanced Course that starts your junior year. Once you start your junior year you will sign a contract and start to receive your ROTC Stipend, $450.00 per month as a junior and $500.00 per month as a senior, this is paid for the months you are in school, plus some during the summer between your junior and senior year. Just remember, if you are not awarded a scholarship the Army will not be paying for any tuition.