I won a 4-year national scholarship out of high school. I am now an MSIII. Does this guarantee that I'll get active duty if I put in for it? My PMS said he never heard of a 4 year winner not getting active.
No. There are no guarantees unless you attend an SMC. Your placement on the OML will be the determining factor if you want active duty. That being said, as long as you've been performing well and have a decent GPA I expect you would get active duty if that's what you desire.
Agree with Kinnem. The needs of the Army will vary year to year. Currently there is a demand for Active Duty officers. That could be different a year from now. Your rank on the OML will dictate if you get AD or not.
To maximize your chance of AD:
Get a high GPA.
Get a high APFT score
Excel at Advanced Camp next summer (very important).
Try to make Distinguished Military Graduate
Here is the OML chart for 2019. (I have not seen what the 2020 chart looks like yet).