I was never exposed to horses as a child, but I’ve been absolutely crazy about them as long as I’ve been alive. So no, I don’t think it’s difficult to be passionate about something until you’ve been exposed to it.
Yes, folks can acquire passions, but rarely does horse ownership turn into a full-blown obsession, unless they’ve always wanted a horse since they were wee people.
I can understand finding an interesting hobby as an adult, but it rarely turns into a passion unless the desire for it has been there most of one’s life.
I didn’t say it was impossible, but for most people it’s improbable to suddenly realize they’re passionate about horses, after having finally been exposed to them.
Case in point; I’ve discovered an interest in motorcycles the last several years. I plan to have one at some point, but it’s not an overwhelming desire. It’ll be fun, and I plan to take all the requisite safety courses, but my true passion is and always will be horses.
For some people it’s sports, for others it’s boating, or any one of a myriad of things, but the real, true passions usually start when someone’s a child.