The UK has a practical minimum of 18 for Prime Minister (technically there is no minimum but practically there is) but realistically never elects a PM under 40.
For British Sovereign there is also no limit, any particularly young Sovereign has effectively delegated to a council of regents historically. In practice this is also unlikely - although in theory of course we are two untimely deaths from a 12 year old taking the throne.
Between 35-60 at start of term, IQ above 130.
I don't think it is. 18 year olds are smarter than most people give them credit for. They probably know math better than most 40 year olds just given their adjacency to math practice in school.
Some of the smartest people I’ve ever known at any age have been among the worst at “life skills”.
Math is at least important in many life skills most would consider important imo. Like budgeting, financial planning, retirement planning, investing, etc.
I'm not in favor of restricting at all the people they can vote for. Let them elect an Iraqi toddler to be US president for all I care; if they're the ones taking care of us, they probably have a good reason.
Just as a thought experiment: what if the threshold for having a vote was tied to paying a positive amount of personal income tax, and the weight of each vote was proportional to the amount paid? How skewed might such a system be? My first reaction is that in countries with high inequality, the wealthy would disproportionately influence the outcome. However, on the other hand, if people avoid or minimize paying taxes, they would lose the power of a weighted vote, which theoretically could incentivize paying taxes in full.
Right now, the top 10% pay about 70% of federal income taxes, so your plan would effectively make 90% of the population's votes effectively worthless.