One of the pros if the age was lowered, underage drinking can be supervised in settings such as bars and restaurants vs college dorms and fraternity houses. Turning 18 is a celebration to adulthood for many. You can do many other things at 18 such as smoke cigarettes, vote, get married.
Alcohol consumption should be there too right? Drinking wouldn't be considered “breaking the law” either if it was changed. Since many college students participate in underage drinking. A fake identification card won't be needed.
With it being pros it's also cons if the drinking age was lowered. Drinking at a early age can cause health issues. It can also cause addiction at a young age if consumed too much. If you go overboard, but if consumed in moderation this won't always be the case. Another con is more accidents in younger age groups may occur. This can be avoided if people wouldn't drink and drive in the first place.
I personally believe the drinking age should be lowered to 18 from 21. It would keep majority of underage drinkers safe. Especially in my experience because I engaged in underage drinking myself. It's cons in every situation but I believe the good outweigh the bad if it was lowered. Life is too short to see the bad in everything, enjoy life!