If you have received an email from Google regarding new age-based restrictions (see example image), understand that is a general notification to (all) Google users. The changes Google is making is basically out of our control other than the limited options they provide, at the time they choose to provide them.
Here at KPS, we have already marked staff accounts as "over 18". On the other hand, student accounts ARE marked as "may be under 18" by default and will need to remain that way for now. These are currently the only settings Google provides and we are not yet certain of what the "user experience" (for staff OR students) will look like going forward.