When my middle son was two years old, I often dressed him in a tshirt that announced "WARNING! I am two." I thought this was fair warning to others, and funny at the same time. I mean, most people know two year olds can be impulsive and mercurial. It's the way two year olds are supposed to act.
In the last few weeks I've had an almost overwhelming desire to dress the same son in a shirt that reads "WARNING! I am thirteen." Not that he would wear it. But others might need the warning because they may not remember that thirteen year olds are also impulsive and mercurial. And moody and forgetful and arguementitive. The tshirt would be useful because visually, it's a bit hard to detect a 13 year old. For my son, his braces and Bieber hair should give it away but his height and stature suggest an older, more mature young man, which is about to emerge. Any. Day. Now.