Bookinglayer calculates the Guest's age through the Birthday field. The birthday field can be found on the Booking Form, the Customer Portal URL and the individual guest profiles in your Backoffice.
Here is how your Guest age is received or adjusted:
Through the Backoffice
1. Click on the Bookings module on the left side menu.
2. Select the Clients tab.
3. Click on the Guest tab
4. Click on the guest name who you want to edit
A side-menu will appear on the right hand side that allows you to enter all the details for the selected guest.
Through the Customer Portal
Your guests can fill out the age field through the Customer Portal URL. Here the guest has the option to enter Birthday details and any other relevant information. See an example of the Customer Portal URL in the screenshot below:
Refer to this article in case you want to know more details about how to send the Customer Portal URL.