Every now and then when you go to share a link to your site on facebook it will pull old content. Don't worry though it is a known bug with a quick and easy fix.
Facebook has a Sharing Debugger. You'll want to put your link in there and it will then see the information that is used when your website content is shared on Facebook, Messenger and other places.
You will see what meta tags the crawler scrapes as well as any errors or warnings.
The debugger also triggers a scrape of your page, so if you do have errors in your HTML you can use the debugger to update your content.
Once you are readyClick the "scrape again" button to fix the issue with old content. and with that you should be good to go.
See Facebook's guide on Updating Objects to learn more.