Updated: Dec 20, 2019
Following on from its recent addition of a new age-gating process for incoming users, Instagram is now also rolling out an option which will enable brand and creator accounts to set age restrictions for followers of their profiles.
Businesses can also set variable age limits for different countries, which could be particularly helpful for brands that are looking to adhere to regional restrictions. For example, in Australia, people can drink alcohol at age 18, but in the US, you need to be over 21 to consume alcohol (in most regions). Those thresholds vary again for advertising purposes, and for brands which do sell products aimed at different age groups, the option could help them avoid any such concerns, while also marketing to a more focused group.
Source: Social Media today; Instagram Provides New Age Restriction Options for Business and Creator Accounts. https://www.socialmediatoday.com/news/instagram-provides-new-age-restriction-options-for-business-and-creator-acc/569467/