This feature is available from version 2.1.0 and later.
The Age Verification feature allows you to restrict access to your store by requiring visitors to confirm their age before continuing.
You can find the age verification section in the Overlay group. Please click Add section to add it to your theme.

Settings
Require date of birth: Enable Require date of birth if you want customers to enter their full birth date (Year / Month / Day) instead of simply confirming their age.
Minimum age: Set the Minimum age required to access your website (for example, 18). Visitors who do not meet this requirement will not be allowed to continue.
Show again after (Days): If a customer closes the popup, it will be shown again after n days.
Action after cancelled: Choose what happens when a visitor clicks the Cancel button: Stay on the current page, or redirect to another page or external website.