SMP is a great program for folks already in the ARNG and Reserves that want to (a) get their degree done cheap or free, (b) get a commission, and (c) potentially want to go AD. Only "B" applies to you.
I'm not Army, but I've been in awhile. It's always best to go the logical, "normal" way about things when it comes to anything military, especially when you are dealing with training and accession. You will have plenty of wrenches thrown your way on your path to a commission. Is it really smart to deliberately complicate things for yourself before you even begin?
As I'm not Army, I'll leave my input there.
I'm not trying to complicate things like I was before when I wasn't sure of my options. As for the letters, potentially all 3 apply to me. I don't
need the money but it would definitely be helpful. and I want to go AD if possible (I'm ok with RD as long as at some point I'm able to go AD). My school is working with me on everything, not my recruiter.
While I'm in school, its only 2 days a month. That doesn't nearly come close to eating away at my competitiveness at ROTC.
Your school may be working with you, but here is what I can say from my experience with SMP cadets.
First off, at the school I go to, our President is a retired Admiral from the Coast Guard. He worked with the National Guard unit that is stationed on our campus (the armory is literally on our campus), and made a deal with them to not deploy any students (whether SMP or enlisted) while they are here working full time on their degree.
For the most part, it's been good. But..
There are friends I know, who were with me last semester, and are now deployed for 6 months and won't see them again till the next fall semester. No matter what things are said, BIG Army has the say in the end.
Another thing I want to point out is that my cousin is doing the same path you are doing. He graduated high school the summer of 2017.
He is just now starting his first semester of college. Why? He was told by his recruiter that he would be able to go to basic and his AIT over the summer and into the fall. All he would have to give up is the fall semester.
This didn't happen. His basic was postponed till the spring of 2018, and he had to wait for AIT school until fall of 2018. After this semester of school, he found notice that he will deploy in the fall. After this, he still has another semester to complete his freshmen year in order to contract SMP for his sophomore semester. Which means, he still has a chance to deploy after his second semester next spring...
We graduated at the same time in high school. I will graduate college and commission 3 years ahead of him.
As far as drilling just 2 days a month... Granted this was all when my cousin wasn't in school, but over the winter,he wasn't able to come to family Christmas because he had drill. He's also told me he's missed a lot of fun things with friends, family, and everything else college students experience. From my perspective as a college student, it's a different life then high school. Typically courses are harder. You have to take care of yourself. Extracurriculars, work, family, ROTC, and everything in between can be encumbering. You'll be surprise what "just 2 days a month" will mean to you.
You also said you don't need the money, but it would be helpful. You can always get a job on campus whether it be work study, a waiter, or anything else. There are always opportunities to earn 3 or 2 year scholarships at your unit.
As far as service time and experience, reserve vs active duty service is very different, and I wouldn't necessarily compare one to the other.
I'm not going to reverberate what everyone else has already told you. You are choosing to serve, and that is very noble. Good luck on whatever path you choose to take.