Is there a way to show the warning message before filling in the form?

Is there a way to show the warning message before filling in the form when the form has reached the limit of submissions?

I would recommend you to manually disable the form. Go to the "Settings" menu and then click the "Form Settings" option. Change the "Form Status" to "Disabled". You can also edit the "Warning Message".

Here's what the users will see if they tried to open the form:

Hope that helps. Thank you.