My Account can not create Database

You can create a database by following the instructions for the database you wish to deploy at the link here:
https://www.linode.com/docs/guides/databases/

Alternately, you can deploy your database through the Linode Marketplace here:
https://www.linode.com/docs/marketplace/databases/

If for whatever reason you are unable to deploy a database by following the steps above, you may need to open a support ticket with Linode/Akamai customer support to inquire as to why you are having issues:
https://www.linode.com/docs/products/platform/get-started/guides/support/#create-and-manage-support-tickets

In most cases this is due the size or specifications of the specific plan/compute instance you are trying to deploy, but they should be able to definitively answer any questions or concerns you have on this.

I hope that helps!

-Micah