I'm falling in with the dinghy crowd. I don't think there's any aspect of sailing a small boat that doesn't create a foundation for sailing a larger boat. You'll learn how a sailboat behaves.
I wish I had a more specific reference to the following...may have been WWII? Anyway, the U.S. Navy found that the best handlers of warships were those who learned their boating skills on small boats like rowboats and dinghies. You develop an inner sense. Those who didn't have that background never gained the innate sense of how a boat moves through the water.
I started on a 12 foot rowboat with a 3 horse on it when I was eight, and started with a 16 foot sailboat when I was 20. Sailed the heck out of it. Also sailed sunfishes and Hobie Cats.
When I moved on to larger boats, currently a Catalina 309, I had a few things to learn, but NOTHING to unlearn. It all applied.
Yeah, I see that you want to eventually charter. I'd still go the dinghy route. Have fun and learn to really love it. I'd put the chartering as a secondary, down the road ambition, with being a well-rounded intuitive sailor as the primary goal.