In 1971, the voting age was lowered from 21 to 18. You can thank the legislative branch if you like that idea, and you can blame the same branch if you don't.
The legislative branch includes the Senate and the House of Representatives, which together are called Congress. Most of Congress's work happens in committees. The Senate has 16 standing, or permanent, committees. The House of Representatives has 20. These include committees on Education and the Workforce, Energy, Veterans’ Affairs, and Homeland Security.