Ooooh. Now this made sense. You were sitting in one of those image editing photo booths, like you might see at a carnival or something. It made sense that a magic shop had one of these... you guess.
Looking over the options, you see a number of them that pique your interest. There were options to change your gender, height, body build, and even race. It was like Photoshop before Photoshop was even a thing, judging by the quality of the screens on this old thing. You take a minute looking over the choices. Then you spot the Age options. Like most 15 year old boys, you've always been eager to grow up and go out into the world. You've also always been curious what you'll look like by the time you're an adult. and all of your secondary sex characteristics have kicked in.
You shrug to yourself. Heck, why not? It only cost a single coin. You could get more of different types later. Let's try the age option first.
Selecting the option, another message appears. "Increase Age: 00"
You weren't quite sure just how old you wanted the photo booth to make your picture. Shrugging, you decide on 30 years old. It was after your youthful 20s, but before your middle-aged 40s. It was the age when you would truly be a man. You brace yourself to be somewhat disappointed, though. This booth was obviously old and was probably only going to distort your photo slightly and place a filter over it. Heck, there were probably iPhone apps more powerful than this thing.
You wait for the bulb to flash, but nothing seems to happen. You're about to leave when you notice the video of your face looks different. It looks more mature, with a touch of shadow at the jaw, like a senior in high school, or even a college student. Wow, this thing was better than you expected. It was actively mapping the changes to the video of your face. You can even see a chin goatee appear on your face, along with a pair of sideburns. You also catch a glimpse of hairs beginning to poke out from underneath the collar of your shirt. Your turn your head, admiring the changes. Heck, if this booth was at all accurate, you were going to look pretty good in a few years.
You continue to watch as your image ages through its twenties. A faint, but thick stubble alights on your jaw, with an amused grin on your face. The changes have become more subtle, so it's more difficult to tell if your picture is still aging or not. A flicker of movement to the side directs your attention back to the secondary screen, where you entered your age. You see a different message reading "Current Age" with a number below it counting up. "26, 27, 28, ..." Ah, so it was almost done. "29, 30, 31, 32, ..." Wait, wasn't it supposed to stop at 30? Then it dawns on you. Before, it was asking you how much you wanted to increase your age by, not what your ending age was supposed to by. Ah, well, what would a few extra years, hurt? This was still entertaining.
Looking back at the video screen, you can see your hairline was beginning to retreat back ever so slightly. Interesting, this was about the age your father's hairline started receding as well. You briefly wonder how the booth was able to calculate that. You then notice that your cheeks seemed to be becoming rounder. Not long after, a second chin appears below your first. You smile and shake your head. So, the booth apparantly thought you were going to put on weight as you got into your late 30's, eh? You had vowed not to follow in your father's footsteps as best as you could. You couldn't do much about the hair loss, but you could at least make an effort to keep yourself fit. As you enter your 40's, you notice your hairline was now noticeable receded, making a defined M shape. You were now older than your father, at least in the image. Touches of grey start appearing at your temples, and in the stubble on your chin, not quite long enough to be considered a beard. You also notice lines starting to appear in your forehead, at the corners of your eyes, around your mouth, and as rings below your eyes.
"43, 44, 45." Ding!
A chime sounds from the booth and and secondary monitor flashes the number 45 at you, letting you know it had reached the end of its program. You chuckle to yourself, the sound being oddly deep, as you look at the overweight, middle-aged man sitting in the image in front of you. It looked like you might in 30 years. The hair loss wasn't so bad, definitely not at worse as you thought it would be by that age, but the weight was an issue. At least you liked like you would be capable of growing a decent beard.
The main screen flashes the message "Retrieve Your Photos Outside" before going dark. Amused, you decide you might try another of those options after getting your photos back. You remove yourself form the booth, which took more effort than it should, and retrieve your pictures from the little slot by the door. Each picture seems to depict you at a different stage along your age progression, starting at 15 and ending at 45. Once again, you are amused, and maybe a tiny bit amazed, at the quality of the pictures. That's when you notice something off.
The hand holding the string of pictures, your hand, looks odd. It appears bloated and thick, the fingers calloused and a bit stubby. The knuckles are covered in hair, as well as the forearm their attached to. Looking down, you see a large, round from pressing out from the inside of your shirt, which seems much, much larger than it should have. Slowly, you reach up to your face and feel thick stubble, the structure beneath, round and doughy. You make your way to a nearby mirror, noting a dull ache in your lower back. The image you see is identical to the one in the last picture in the series you're currently holding. You ran your hand through your thinning hair, noticing the balding spot in the back. A look of surprise and disbelief manifests on your face. The booth hadn't just made a picture of you looking older, it had made you yourself older!