Use the [Flag](https://www.drupal.org/project/flag) module to flag a user when they first submitted content that fits your requirements. To flag such user create a rather basic rule like so:

- Rules Event = After saving new content.
- Rules Condition = whatever fits (if any).
- Rules Action = Flag the user.

Which the above in place, improve your existing rule to check if the user is flagged.

***Easy, no***?