Reasons against lowering the drinking age - points to talk about?

I'm writing a research paper that's due in 2 days and it's about lowering the drinking age. I first took the side of lowering the drinking age, but then i realized there's more facts and reasons not to lower it and it would make for a better research paper. I need to come up with 3 preview points to talk about for my body paragraphs. Any suggestions for points to talk about? enough to write 5 pages? please help!!

US is the one of the very few countries with drinking age of 21, most of them is 18
you can find additional information here hope it helps

potsdam.edu/hansondj/LegalDrinkingAge.html

Just go to google and look up "drinking age debate." You will find many articles from legitimate websites that you can cite in your paper, such as USA Today, 60 Minutes, etc. There is tons of information out there. You just have to look for it.