You decided to wish yourself older as well. But have to be one up on Matt. You can't let him have all the glory.
So You make your wish," I wish to get 15 years older and gain 100 pounds for each minute of the next few minutes. But my clothes will suit me perfectly as it happens."
Thinking that should do it. You rush back in the store to the bathroom and look in the mirror, which so happens to be full sized for a perfect view of most of your body.
You wait. But not for long. Because very soon your stomach feels warm and sort of stings. You watch as your belly is stretching outward, and outward, in a big ball of fat. You look at your hands and notice that they are like little sausages, when you flex them they even feel thicker. You continue to grow and watch the mirror as you notice your arms are much thicker as are your legs. You can feel your face become much fuller and see it changing into a much more mature face. Your chest is getting much hairier. And your belly is sagging lower and pushing out much more. The minute must be up you think. As you look about 30 years old and weigh probably 250 pounds.
But the gaining just keeps going. As does your facial features. your getting older and growing a full beard. It's dark brown and you look like a true bear of a man. Your belly is now a good 50 inches around and your clothes are still fitting you just as you wished. But you have noticed that they have changed a bit. Instead of a t-shirt you once had on a button up shirt has replaced. Because you soon don't care for your already huge belly is now pushing farther out. Wondering when in the world it will stop you look back up at your face and noticed that you are starting to bald and your hair is turning grayer. Your beard and mustache are now very full and has gray spots all over it. How old did you wish yourself?
You keep looking as long stripes appear over your shoulders and down your shirt and you notice that suspenders are forming and keeping your pants up from and your belly is well pushing 400lbs.
You suddenly feel it all stop.

You take one big look at yourself.
You seem to be about 60 years old. With a very balding head. Just the grey bowl of hair over the ears. Your beard is big full, and very white. Your belly extends so far it will be hard to touch your belly button. Suspenders now tightly overlap this mound of fat. The only thing keeping them from the floor. You also feel very tired, so you sit down on the toilet seat for a few minutes.
You try to clear your thoughts. But you can't help but stare at yourself, rubbing your massive belly.
You are now a 60 year old huge man. You look like a much to fat Santa Claus.
You want to immediately undo the wish but realize that you left your Wishing Powder outside with Matt.
So you slowly waddle your way out of the bathroom to get it.
But you notice that.