24 here. Pretty sure early 20's pipe smokers are a rarity. 18 year old pipe smokers even more so! There's no reason this hobby shouldn't or can't be enjoyed by the younger crowd. Nowadays with the internet and everyone being connected 24/7, you can learn more about pipe smoking in a week than in a year before all the technology. Something that should also appeal to 20-somethings, is the affordability of pipe smoking. If you do it right, you can smoke pretty darn cheap on a pipe. Good MM cobs are dirt cheap, made well, and don't require a whole lot of special attention. Pipe tobacco is relatively cheap also. My local tobacco shop does $3 an ounce on their "house" blends. And good tins are inexpensive as well. Most hovering in the $10 range. Im into craft beers, single malt scotch, small batch bourbon, and pipe tobacco is by FAR the most affordable of my vices.
Sorry for the long winded post. Us young people are an excitable bunch 8)
