Lower the legal drinking age back to 18

Before changing the drinking age to 21 it used to be 18 here in the U.S. as an 18yr old who is fully independent, paying rent and bills etc while working 45 hours a week managing a restaurant I feel that myself and my peers are mature enough to be able have a drink. We can go fight to defend our country, sign a contract, be prosecuted as an adult, and have all other responsibilities and rights that come with being an Adult in the U.S. However, we can not legally share a beer after work. Not only is this unfair treatment but it makes it "cool" in some peoples eyes to consume the forbidden substance or even sneak into bars. Its time to go back to the age being 18!