Hey @AhmadFagieh looks like you're trying to access it from the wrong spot, you should see a menu option next to your sign in location in the top right (9 dots) that is where you can access ArcGIS Dashboards from,
You are currently logged in with an Esri Public Account (may be same as My Esri Account). You haven't activated your ArcGIS Online organizational account that comes with ArcGIS for Personal Use subscription.
You would have received an Order Fulfillment Confirmation mail from Esri.
Use the fulfillment page link to navigate to My Esri , where you will see the option to activate your ArcGIS Online Organizational Account.
You can then create ArcGIS Dashboard from ArcGIS Online account. Even your ArcGIS Pro license is managed from your ArcGIS Online Organizational Account.