Welcome! If you really want to learn about horses, I'll quote the others as I say find a trainer! Make sure they're reputable - do your research. But as for me and my riding journey so far, I'd love to share (:
It started when I was a baby, I was raised alongside horses. Got my first pony at 5 (she passed when I was 9). Had a hiatus, then took up real riding lessons in barrel racing and pole bending. Had a nasty accident and wouldn't touch a horse for 8 months. Then got back into lessons, this time doing Dressage. Got my horse after a little less than a year. I've had her for 2 years now. About 4 months ago I left my old trainer and found a new one, starting yet another new discipline; jumping! I think I'll settle down now lol. I'm very happy with my current trainer and am improving tremendously. The thing that taught me more than any trainer or book ever could; however, was my horse. She taught me patience, trust, and perseverance. And of course, I now know how to identify and treat Line Disease, Thrush, Suspensory Ligament tears, popped Splints, Founder, and Hematomas.
c'est la vie