Checking availability on a calendar

Hi

Looking for some advice on whether what I am trying to do is possible.

I want to have a calendar to book in visiting children to a school, I need to be able to look for the next available date where there is NOT a kid visiting already who is in the same year group and gender.

It doesn't have to be a calendar if this is possible with a list.

Cheers for any advice. Still pretty new to SharePoint and it's probably really obvious.

Thanks again

Jason