Hi Julia!
I also love visiting Walt Disney World in October! It can be tough to visit during a different time of year if you are used to visiting in the fall when crowds are low and weather is mild. September and October are definitely less crowded than other times of the year. However, the parks are usually open for longer hours in the more crowded months of the year, including May and June, so you can fit in a lot during your day.
May is less crowded than June, as many schools have not yet let out for the Summer. If you avoid Memorial Day weekend, you may be pleasantly surprised at the crowd levels. Visit in early May, as it's after Spring Break, yet before Summer, so it can be a great time to visit.
There are great ways to navigate the parks during the more crowded times of the year, including staying on site and taking advantage of
Extra Magic Hours. I also suggest getting
Park Hopper tickets so you can take advantage of visiting multiple parks in one day.
Magically,
Stacy