Question about aging and starting a new equine relationship

Recently someone was taking an informal survey, asking about middle aged riders who are "starting again with a new equine partner." I have a few thoughts to share.

There are three aspects of a new horse that come to mind right away. Mind, movement, survival instinct in action.

Until I am mentally and physically comfortable with those three, it worries me a little (or a lot in which case I don't mount) to ride a horse.

This can and does apply to the horses I own as well as horses new to me.

Mentally -- is the horse available mentally? Able to be calm? What does it understand? How does it respond? is the horse comfortable learning new things?

Physically -- can my body move with this horse's body? I have mostly ridden horses with smooth gaits and shorter strides so my body is not used to sitting the trot of a long strided larger horse. I bring that deficit however I'm working to change that, and "even at 61" I am making great progress primarily under the guidance of a physical therapist who is gifted beyond my imagination.

Survival Instinct -- how does this horse react when his/her survival is threatened? I came off my Morgan mare a few times before my body learned how to stay with her when she did her particular and habitual survival moves. It took a while to get familiar with my Morgan gelding's moves, mostly because I wasn't aware at the time of what he was doing because I was 'expecting' unconsciously in my body that he would move like she does. Not. I can ride with him now that I know his biggest, worst moves -- know these moves in my body, on a cellular level about which I need not think.

Of course at this point in my journey, I am seeking that mind-to-mind comfort before I ever mount, so that as long as I am paying attention to our relationship and responding responsibly with guidance in a calm fashion, those bigger moves should never surface. I'm getting better and better at judging what the horse needs from me before I even mount (and what I need from the horse), so that my rides are 'uneventful' compared to what I have expected, allowed, and experienced in the past.

I have 5 horses at home, one has never been ridden. I at times ride any of the 5-7 horses at the therapeutic riding program where I work as an instructor, volunteer trainer, and consultant to the horse herd coordinator. I'm approaching the older end of 'middle age' and am increasingly cautious because I hate hurting and being in any way incapacitated. That caution translates to more time on the ground establishing connection -- especially mentally with the horse, and physically with my own body. I'm pretty dedicated to a life time of getting better at what I love.