It is absolutely realistic! You can 100% do it, and the way you have it planned out is exactly right! There should be a whole club of us: middle-aged women who maybe rode a little when they were kids, who now want to ride and maybe own one day.
Just briefly about me, I started riding in Feb of 2018 and (rather unpractically) bought my two horses in April of that year. Then I spent the next nine or ten months frantically learning everything I could about horses, while getting to know the guys I had bought. In January of this year I took on a third horse, who was free and came with a sob story about how he was neglected and anxious, etc. etc. It was true -- he really was worried and anxious about everything, but I got to know him, worked with him, gained his trust, and now he's a great riding horse. I board my three (am looking to buy land hopefully and then move them out there in five-ish more years once I have more knowledge); they are usually kept in their own pasure and are a really amazing little mini-herd (I always get compliments on how nice they are and how well they get along). I did it the dumb way (buying horses before I knew anything about owning horses) but it has worked out OK. This forum is a GREAT place to get advice, also!
Anyway, the point being, you can absolutely do this! I think everything
said is exactly right. I would personally recommend picking up a book or two by Mark Rashid. He is less about specific instructions on training or riding horses and more about understanding them.
The only thing I might suggest is that if you do want horses on your own land, you should probably plan on having more than one horse, as most horses really prefer to be around other horses. Or at least some sort of companion animal. People will disagree with this, and yes it does depend on the particular horse's temperment, but I would not plan on having just one horse.
ETA: and I will add the one piece of advice that I got from multiple people, and I think it's the best piece of advice I got about understanding horses. Spend time just watching them. Hours at a time if you can. Watch them in the pasture, watch them in a corral, watch them in stalls, watch them wherever you can. In my case, I believe that all of the time I spent watching (it was a LOT of time!) sort of fast-forwarded me into a place where I am able to sort of understand horse body language and what horses are thinking, just from looking at them. This is a knowledge that I think people who have been around horses all or most of their lives take for granted, but for people like us who are starting late, it's just super important.