DeltAlum,
I'm going to "assume" (you know what that usually does
) but I think the penalties for underage drinking now are stronger than they were when you were in school. (For example, losing your license) I think nowadays if you could get beer and not get hassled about it, you might just stick to it and not push it w/ liquor. Plus, we were all so poor that we drank beer out of necessity, not cause we liked it (well, at first LOL).
And I know this is a Pennsylvania thing, but since we have to deal with liquor store hours, beer is usually just plain more convenient.