If you can vote like an adult, you can be tried as an adult, drink like an adult, apply for a credit card like an adult. If you think a 16 year old can successfully navigate these obstacles, then you go right ahead and let them vote. Hell, I worry about most 18 year olds.
How about this, so long as you are 16 and paying state/federal income tax, then you can vote, but if you are a 16 or 26 year old snowflake deadbeat living in your parent's basement, then "no vote for you."