Hello cayla1984,
Welcome to Apple Support Communities!
If we understand your post correctly, you forgot the password to your MacBook Air as well as the firmware password and all the options in Find My are greyed out because you haven't set it up so you want to know how to factory reset your MacBook. We're happy to help!
Before you factory reset your MacBook try the steps in the article below for resetting your Mac password.
Change or reset the password of a macOS user account
If you can't remember your firmware password, schedule an in-person service appointment with an Apple Store or Apple Authorized Service Provider. Bring your Mac to the appointment, and bring your original receipt or invoice as proof of purchase."
For more information about the firmware password check out this article: Set a firmware password on your Mac
Let us know if you have any questions.
Thank you for using Apple Support Communities.
Take care!