why isn't MacOS downloading on my MacBook Air if its compatible?

Hi ElenaMarisol

Thank you for using Apple Support Communities. We understand that you are trying to upgrade your macOS, but you do not see it downloading. We'd like to assist.

Thanks for reviewing: How to reinstall macOS

Have you followed the steps here to upgrade? Update macOS on Mac

If so, are you seeing an alert or error message when you try?

You may want to start your Mac in safe mode and try to update. Here's a guide with the steps to start up in safe mode:

How to use safe mode on your Mac

We hope this helps.

Cheers!