We don't use teams

You can just have one age group per team. You can rename the teams to match the age groups, if you like.

All of this can be managed from the settings section. (A link to settings is at the bottom of the left menu.)

You can use Age Group settings to define the age groups you will be using.

You can use Team Settings to manage the team details.

I don't know enough about how you are managing rotations to make any recommendations there. The suggested rotation schedule is built based on the recommendations in the VBS Director's Guide. If your schedule is too different, the scheduling tool may not work for you.