No matter how physically fit you are when you first ride a horse, it doesn't prevent you from experiencing all the joys of beginner horse riding. This is for two reasons: 1) Riding "fit" is different from any other type of "fitness," and 2) Riding is less about muscle and much more about feel, confidence, and balance.
That being the case, it's impossible for a beginner to advance any faster than is safe or reasonable. After your first lesson, you literally can't move the next day, so going from never riding a horse, or only pony riding at the fair as a kid, to riding 8 horses a day is just not feasible.
Riding a bike is a skill acquired by most in childhood. The oft quoted phrase "It's just like riding a bike" exists for this reason. The actual, basic, physical action of bike riding doesn't take years and years of patient skill to pick up. Linking into this, the stronger one is physically before they start, the stronger and faster they will become on the bike in a relatively short amount of time, given they put in the miles and read up a little bit on technique.
BUT. Being a STRONG rider and being a SKILLED rider are not mutually exclusive.
Cue my entrance.
It's safe to say that I entered the sport at a relatively high level of fitness. I'm not Wonder Woman (though I do still have my costume from when I was 5), but I'm not a couch potato either. I've also read up and put in the time on the bike. The result? I can currently keep up with a solid B ride in terms of fitness and strength.
What do I lack?
Here's a brief story:
Last night I did a Ladies Training School B ride. We were doing a running pace line, keeping up a solid 18 mph average, and generally working our butts off. We were also not stopping. Finally, after about 12 miles, being completely parched, I called out to the leader, "Can we stop, please? For a second?"
Assuming I needed a breather, since I it was my first time out, he acquiesced. When he saw me immediately dive for my water bottle, he was incredulous.
"We're not stopping so you can DRINK, are we?"
Yes. We were.
Are you getting the picture?
I can keep up an 18mph average, and stay with the front group for the sprint to the finish, but then I fall over in the parking lot because I'm so psyched I stop paying attention to which direction I'm leaning. I can push up a hill in the big ring, but I fall over when trying to negotiate a tight opening in a gate when turning onto the Greenway from Strawberry Road.
I'm strong. But I'm not skilled.
It's an odd place to be, for sure. I'm excited to ride how I'm riding now, but I know that only good ol' fashioned time will give me the skills I need to really advance. Unfortunately, time moves at its own pace.
But also fortunately, I'm not too proud to sport a camel pack in the meantime.