Until 1912, flags weren't as proscribed as they are now. Much was left in the hands of individual flag-makers. At one point, there were 15 stripes and 15 stars — honoring Vermont and my home state of Kentucky, in addition to the original 13 colonies.
But adding a star and a stripe for every new state became cumbersome, and by the early 19th century, new states earned a star but not a stripe.
Now our flag has 50 stars, of course. I wonder if there will ever be more.