That takes between 10 days and one month. We had a U-St. ID Number after 2 months with a tax number far earlier in most projects.

You can, if the Impressum is an issue, state in the Impressum "Steuernummer: Beantragt, erwartet Registrierung."
This is factually right and from the moment you have your "Gewerbeanmeldung" you should be allowed to do business. Don't worry about that. The Steuernummer is NOT necessary for the Impressum before it has been issued.


However, make sure you get everything else right. I would in fact not state much about AGB, if you do want to stray from German law. Most retailers have huge walls of text that in fact do not even fucking differ from BGB and HGB law...