screen share

Welcome to the Zoom Community, @Kristin50.

There is an option in Settings to disable screen sharing; it would be odd that this is set to disabled, but it's the only thing I can think to check.

I know you might be the only person on your Zoom account, but take a look at this Zoom Support article which explains how to enable/disable screen sharing at the Account (organizational account that applies to everyone on your account... even if it's "just you") and the User level.

https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0058726 

Here's how mine looks (you have to scroll to locate this part!):

If, where my switch is blue (white dot to the right) and yours is grey (white dot to the left), switch it to Blue/Enabled.