Science has discovered that the age of 25 is when neuroplasticity starts to decline. So what? There's a lot of argumentation needed to link that physical thresh

Science has discovered that the age of 25 is when neuroplasticity starts to decline. So what? There's a lot of argumentation needed to link that physical threshold with legal restriction. It seems like you're arguing that people shouldn't fully participate in society until they start losing their ability to learn. Have you met people who've lived overly sheltered lives until the age of 25? Their tolerance towards risk is low. Their ability to adapt to new experiences is busted. Forcing that on a society wide scale would be nuts. The science does throw in a lot of complexity between the social ideas of freedom and the physical effects of alcohol. But have you met 18 year olds? They're drinking.