By twenty, an average human being has typically experienced a lot more than your average teenager. Between the ages of 17 and 20, teens must prepare incredibly quickly for the future ahead of them. Essays, applications, resumes. The shift from the shell of high school to adulthood happens very fast. By raising the age requirement, voters would be able to become more well-rounded individuals, fully shaping and identifying their views and opinions before contributing in a vote. They would be able to experience the beginning of what adulthood is really like and understand more how policies affect them, rather than making assumptions.
Many young adults have experienced things in this life that adults years older than them have never even heard of. Comparing experiences to the different age categories is not an accurate method of scoping out a proper minimum voting age requirement, as people can have different experiences and mature at wildly different ages.
[P1] The older one gets, the more life experience they gain. [P2] Educated and quality votes require life experience.
Rejecting the premises
[Rejecting P1] People gain life experience at different rates. [Rejecting P2] What one experiences shouldn't be required to vote.