You might want to try the idea someone had in Finland, our drinking age is both 18 and 21.
How's that you say, well let me tell you. When you turn 18, you can buy any alcoholic beverage from the store that has less than 20% alcohol, so beer, wine and some liqours are okay. You still can go to a bar and order up a drink that has any amount of alcohol. When you turn 21, you can buy anything from the stores. Point being, that in a bar, the staff will pretty much look after you and call for help if needed, but when you drink alone, you don't drink as heavy stuff.
I'll just remind you, that here we have a goverment monopoly on alcohol retail. Only beer and cider with alcohol procent of less than 8 is allowed to be sold in grocery stores. All other drinks are sold in Alko stores, which are owned by the goverment. The idea behind this is that this way the quality can be monitored, and to prevent the sale for people who are very intoxicated.
PS. This doesn't really work as well as it should, we start drinking around the age of 13 or 14. Finnish people drink the most alcohol per capita in the world. Our drinking culture is all about you getting hammered on spirits. Our "national drink" is Koskenkorva, tasteless 38% spirit, which is consumed in enormous amounts.