Thanks for making this easier for me. Well you just contradict your topic with your very own argument . The topic is " Lowering Drinking age to 18 " therefore its already mean that drinking age should be lowered to 18 and you just said " The legal drinking age should be lowered to 18 years old " and your a con so it means your completely against it. That argument can be valid if your a pro , but your a con. So you see , you just contradicted the topic with your argument.