Are you intending to go rated? If so, do you have any flight hours? The reason I ask is that if you go the 3 yr route, you will be up for rated boards @18 months from now. Rated boards meet @Feb. of your AS300 yr. Flight hours will give you a boost and can mean the difference from getting Pilot or RPA.
I do agree with everyone do 4 yrs. The 4 yr will allow you keep your gpa up. To keep your scholarship you must be awarded an SFT slot as a 250. If not they have the right to disenroll you from AFROTC. Statistically lately your chances are high to get that slot, but there have been years where it was as low as 55% overall, and if you are non-tech/non-rated than it is the lowest chance, low = think around 20%. Your gpa will matter a lot. It is part of the scoring process for selection. It will also be part of the score for your career field.
~ AFROTC might say that you need a min gpa of 2.5, but the fact is that gpa will not be something you want when it comes to boards, be it SFT or AFSC.
The final pro is from a Mom's pov. You will spend at least 4 yrs ADAF. I get wanting to fly the coop and start your career sooner than later, but as a wife of a now retired O5, and a Mom of an O3, you do not realize how deep your family roots are planted. If you do the 3 yr. expect to report to your 1st assignment in 3 1/2- 4 yrs (usually it is @6-9 mos. after commissioning). That assignment can be in Japan, it could be Clovis NM, it could be Fairbanks AK.
~ In the 21 yrs Bullet served, we moved 11 times. The closest we ever came to being by our family was 4 hrs away, and that was at the 15 yr marker. DS has been in the AF for 5 yrs now (pilot) has moved 3 times. (UPT in TX, school house in ARK, Operational TX). Just saying to think about it from a different perspective. One more holiday at home. One more spring break. I can testify and so can my son and his wife, one of the hardest parts of serving is calling home on Thanksgiving and hearing the family noise as the phone or Skype is passed around so you can say hi! It will hit you like a brick. It does not matter if you are going to someone's house or people are coming to yours, you will miss not being there eating and laughing with them. Thus, doing 4 yrs impo is about making more memories with those love and support you, that you will carry with you when you are far away from home.