It can take some time for Facebook to update any content that you've changed on your page. You can refresh this share using Facebook's Debugger tool
1. Go to https://developers.facebook.com/tools/debug/sharing/
2. Enter the link to your page
3. Click Debug
If the information showing is now correct you're all set to share the page. If not you can click the Scrape Again button to keep updating the page.
Please note that this will affect any share made after this point. This will not change any sharing you have previously made so you may need to delete older shares.