I'm 27. I started drinking when I was 13.
When I started drinking, I did it because it made me feel liberated... I mean, I felt like I was getting away with something.... It's a good feeling when you break rules...it was summertime and I was sitting on my front porch with friends killing time. I didn't really binge until I was 17 or so (only did it once before the end of high school), but I did that with good friends and that's when I really got a taste for beer. When I was 18, I started college and knew how to chug with most of the serious brothers in the fraternity I pledged....
Once I turned 21, I had a taste for beer and knew a lot about it. By 21.5 I had already consumed over 250 different bottles. I ended up meeting some really cool old guys that are nuclear and fossil engineers... They brewed their own and I started going to their parties (100-200 people eating german food and drinking homebrew with a band). I guess when you brew your own and make money, you can afford to throw killer parties for the freeloaders.
My whisky, bourbon, and scotch experience comes from the past 10 years. I started on whisky when I was 18. I would mix it with coke and the occasional lynchburg lemonade. These days, I drink Maker's Mark, Woodford, and DeWar's.
Tequila is another story...I didn't really get into that until after I was 21. I mix the best margaritas with 1.5oz of high quality OJ and whatever gold tequila I've got on hand. After going to mexico and hitting the free bars, I had quite a few shots and got to really taste the difference in tequilas.
Take a wine class if you really want to learn about that stuff. I thought I knew a lot...when I sat down with 8 glasses (4 whites/4 reds) in front of me each week for 3 months, I got to truly experience the differences between different countries and grapes.