Should the age of adulthood be raised to 30?

The part of the brain that controls risky behavior doens't mature until the around age 30 to an adult level.People are living longer people are looking younger and 50 years ago 30 was old now its young and 18 is like a fetus so I feel education should be raised and extended to help research and teach more science.The only reason they let 18 year olds fight in war is because of their lack of maturity and they are impressionable and can think for themselves.