I learned on my cousin's backyard pony how to stay on a bucking horse, bareback, at age 9. Don't even ask about helmets...
I'm from Texas, originally, and it seems like everyone in the rural areas has horses hanging around, and so I went on loads of trail rides, and hired horses for trail riding whenever I could - for decades.
Now I'm 43 and I'm finally learning to ride properly (no, people, that is not a slur on trail riding, because good trail riders can keep their horses from eating grass and stuff, and I couldn't). I'm learning hunt seat, and by golly, one of these days I'm going to try jumping. Not any time real soon - ground poles are where I'm at - but I will do it.
AND I'm going to get my own horse...just as soon as I figure out whether I want to do jumping or dressage.
You can do it! You will get so much more out of your lessons than you did as a teenager. Your brain is more mature now than it used to be, and your focus is probably a lot better, and you're better able to translate directions and commentary into useful skill development. These are the HUGE benefits that come with learning stuff as an adult versus as a kid. You'll see - this will be even more fun than it was the first time!