Hello cmpaula,
It sounds as though you’re having issues with Pages unexpectedly closing shortly after opening. Apple Support Communities is a great place for help with this issue!
Deleting and reinstalling the app is a fantastic step to help reach a resolution, and we're glad you had the opportunity to try that step. In addition to deleting and reinstalling, try the first three steps outlined in the following article.
If an app on your Mac stops responding, closes unexpectedly, or won’t open
If you continue to have issues after completing those remaining steps, create a new admin user account and test to see if the issue persists. You can find the steps for creating a test admin account in the following article.
Set up users, guests, and groups on mac
Notate the results, and provide those details to Apple. You can find their contact options via the Get Support website. With the information you provide, they’ll be able to provide additional troubleshooting steps to help reach a resolution.
Take care!