People who suggest lowering the voting age haven’t been spending much time with teenagers. If they did, they’d clamor to get it raised to 35.
Ask a group of 17-year-olds what the Supreme Court does (“like, when my dad had like a speeding ticket, that’s where you go, right?”), what capitalism is (“like what they have in North Korea? Or other bad places?”), or what the president does (“he makes laws!”), but make sure first you have a competent psychologist to help you handle your reaction to what you discover.
(And please don’t tell me how your kid is different. You are probably a college professor or somebody equally intellectually sophisticated. You are not indicative of anything.)