The milestones of aging are great; at 16 you can drive, 18 you can smoke, buy porn, and gamble (Woo!), at 21 you can drink to your heart's content; and after that, there aren't many milestones left. It's great to reap the rewards that come with age, but not looking your actual age can lead to some frustrating experiences.
For the record, I am 23 years old. I have experienced a bit of the perks that come with age. However, I am often told how much I look more like a high school student and less like a college one. For some, being told you look younger than you actually are is considered a compliment, and maybe it should be. But for someone who gets told this quite often, it feels less like a compliment and more like an annoyance.
Something that many readers may relate to is the curse of the "baby face." When people say you have a "baby face," they mean you look much younger, like a 12-year-old boy yet to hit puberty. If you can relate to that, then I am sure you can also relate to trying to buy alcohol and have the cashier not only card you but look at your ID with scrutinizing eyes. The cashier will then ask, "Is this for real?" You then sigh and answer, "Yes, yes it is for real."
Another issue you might encounter if you are a male to look your age, or older, is growing facial hair. I work a summer job with high school kids that pairs blind and visually impaired youth with six week jobs. I'm often mistaken by students and their parents as a participant of the program. While the age of other male colleagues are taken at face value, I am gawked at like people have seen a unicorn. Parents ask, "What job will you be working this summer?" When I tell them I am a counselor, they size me up and tell me that I look like one of the participating students.
Don't get me wrong, looking young may have a few downsides, but it does have perks. You can get discounts on events and movies for faking your age a smidge and maintain a youthful appearance as you grow older while others around you will show signs of age. As those around us develop crows' feet and wrinkles, those of us who bare the curse of looking young will be basking in the glow of a youthful appearance.