Which active duty route would you advise me to take, a 35-series MOS or 37X? Should I enlist as an older soldier?

I retired in 1995, so much of what I know is dated. PSYOP was not an MOS when I started. From the sound of you query, I'd say you're interested in the strategic side. I came to the Army From the Marine Corps, so as a newly minted Intel Analyst I was assigned a tactical (HB) team and went to jump school. I was best suited to that. For you, I'd suggest working on skills that support a focus on skills that support the strategic side with emphasis on areas that concern US long term interest.

All depends on what you really want. 35 series MOS offers so many things and possibilities. The 37 series offers similar - but a whole different world and most of your time will be spent some place else either prepping to go = there - or recovering and starting the process again. If your mind is set to do the job - you will make it through all selection and training. Language is a good item - it and jump pay do add a little extra to your check each month. And agree - food is always an in into a culture... always opens a door.

I'll play my card here.

I enlisted and entered basic training at the age of 39, and was originally a 35F (all source analyst) I'll share some thoughts. I did it. I'm still at it, and now with more years behind my career than in front of me.

Firstly.......... the Intel stuff.

I am astronomically biased that All Source (35F) or Geoint (35G) are the way to go. They tend to have the most civilian market mobility, and the USAF would snipe Army 35G analysts with $100K signing bonuses before I commissioned.

Skipping the semantics of Commissioned Officer stuff, the path way for Warrant Officer is very much on the table. The chances numerically for warrant are also going to be better as a 35F or 35G.

Secondly........ being a new soldier and old man.

1) What pissed me off the most is I couldn't convey any wisdom to the kids. When I tried they wouldn't see me as anything more than a peer. Later in life I learned there was a small group of kids in my Basic Training looking up to me, but none of that is obvious while in basic training.

1a) The main thing I was trying to convey to the kids is just push through the game. Time is finite. For F sake, Basic isn't even one fiscal quarter. I will have gone longer from one visit/call back home to another (basically see the family at X-Mass and not again until the next Thanksgiving), and these kids are falling apart. As well, they thought they could avoid punishments. It's going to happen. Every single one of us could have been prior service special forces NCO's and we will do 1,000,000 push ups. The prior service guys would have called it exercise. For the crying kids it will be called punishment. Either way, regardless, we all are doing 1,000,000 push ups. So the reason is irrelevant. Don't blame each other.

2) I did a police academy (and graduated) before basic training. It was much harder. There I could quite any day and there were no consequences to doing so if I didn't want to push through. The mind games were harder, the physical stuff was harder, and the class room testing was harder.
2a) I could see the Drill SGT's set up the kids for integrity failure a mile away. The Drills already have punishments at the ready all lined up. Nothing I could do about it. It's like trying to stop a train. The only way I could save them is if I stepped in front of the train myself. NOPE!!!!!!!!!!!!!

3) The moment of truth regarding the games was Range Qualification. The entire company qualified on Day 1. We literally handed the Drill SGT's an additional training day because there was no need to use the range for a follow up of prior NO-GOs. They never let up. From that moment I knew this is the way it's going to be the whole time. I couldn't convey that to the kids.
3a) Confirmation of the games. There are three phases in Basic. White, Red, Blue. Each phase is a level of stress for the recruits. White being the worst, where the actions of individual punish the masses, Red being where the actions of the individual punish the offending individual. Blue being soldiers are allotted little freedoms (I don't know what those are, we never got to Blue phase).
3b) As said, we did not get to Blue phase. It was the day of Basic graduation and the Drills noticed the company banner was a red flag, and they couldn't take us to graduation like that. So what they did was replace the red tattered flag with a BRAND NEW STILL IN THE BOX, STILL WITH FACTORY CREASES BLUE FLAG!!!!!!!!!!!!!!

Blue Phase was NEVER GOING TO HAPPEN. It just never was. It was never in the training calendar at all. The plan was to never get there. That was the plan. I kind of figured that by week 7. We got to a point where phases really didn't mean anything. Giving a blue flag would have taken away all the carrots the Drills could dangle in front of us.

4) Physical requirements: I was not the oldest that entered my Basic Training Cycle. There were two others older than myself. I was however the oldest to make it out of there in once piece without a profile or medically discharged. I came pretty close to breaking myself trying to keep up with the kids. The army standard is much lower than one needs to reach for before they risk injury. Do not push yourself to those limits. You do not know the recovery period you will be given. Injuries will occur when you start to lose focus caused by sleep fatigue.

Remember, no matter how much they yell at you for failing to meet the Drill SGT's standards to push yourself it is absolutely impossible for them to kick you out of the Army if you meet Army standards. The company commander can't even take rank away for that reason alone. They can continue to take sleep, and push you to further physical limits, but they can't psychically force you to run faster when you have a Record Passing Fitness Test in your file. You are going to run in circles for 5 hours, so take it at a pace you will be able to function with tomorrow. You are going to keep pushing based on the Drills' ability to observe you, not your ability to appease their standards. So why kill yourself over it. The thing is the kids don't know that and they probably wont take in your wisdom because they are crying for mommy because it's been a week since they last talked to family.

Check the box, meet the standard, do not have a pending Article 15 and absolutely nothing will stop you from moving on after basic training.