Thanks for getting back to us, @nycte!
Yes, the Fiscal Year is a one-year period that starts on the first day of any month. This applies to QuickBooks Desktop, as well as in QuickBooks Online.
Here's how to set your Fiscal Year in QuickBooks Online:
The screenshot below shows you the last four steps.
I'm also adding these articles for reference in case you need tips and related articles in the future:
I'm always around if you have other questions or concerns. Have a good one, @nycte.