State law enforces age restrictions on property in many circumstances. Adults can’t enter school property without registering with the main office. State law prohibits entry into bars and cannabis shops for people under certain ages. State law can prohibit minors from entering adult-oriented shops.

And we not just make lawful but even encourage the creation of housing intended for aging adults: https://www.hud.gov/program_offices/fair_housing_equal_opp/f...