It would be foolish to say that we are not smart. We have some of the highest scores, as recent rankings indicate, and we are incredibly dedicated and hardworking. But what students fail to anticipate are the many other realities awaiting us in the future: living on our own, cleaning the toilet, dealing with demanding bosses and callous coworkers. In short, adulthood.

As we grow and prepare ourselves to join the rest of society, we are bound to have screw-ups and errors in judgment (often serious ones). We do not have the luxury of being “cut a little slack” every time just because we aren’t adults yet. While there may be a difference in maturity between a 13-year-old and and 18-year-old, the perceived shift in maturity from 17 to 18 is almost none. What changes in that year that allows us to take on these responsibilities and difficulties?

We give ourselves a serious reality check.

It is true that the brain only reaches its maximum weight at the age of 20, when the teenage years are over. In addition, at the age of 20, the neurons in our the prefrontal cortex, the part of the brain that makes decisions, are the last to be covered with a protective sheath called myelin that speeds the transmission of electrical signals. It would seem as though science has given us the perfect excuse.

However, this process would not happen unless we sped it along by allowing our brains to grow, learn and think. The brain creates synapses (nerve junctions) whenever we challenge it to work in different ways. These only become strengthened as we continue to stimulate our minds. What happens, one might wonder, when we fail to use our brains?

We lose them. In other words, Homer Simpson happens.

We don’t literally lose them, but it takes longer for us to become adults in the neuroscientific and psychological sense of the word. Our “teenage phase”, while not definitive, can definitely be extended when we don’t try to take on the world and its challenges.

When we place ourselves in new situations, it takes time to adapt. The same is true for adulthood. We do not just become adults overnight, or in one year, for that matter. We are, over the course of our teenage years, continuously evolving, developing and learning to handle these situations. When we drive for the first time, when we have to manage our money for the first time, when we are left without our parents someplace for the first time — all of these are critical learning points for our brains.

Yeah, we are not going to get it right the first time — we are going to need help. But if we fall back on the excuse that we are “just teenagers,” or worse, “just kids,” the idea that there will not be repercussions for what we do because we are “just kids” will be psychologically imprinted on our minds. We will never learn to deal with our mistakes, let alone on our own.

Just as with the law, ignorance is no defense. When one turns 18, the excuse expires, but the ignorance remains. So if you know what is good for you, challenge yourself. Learn how to cook, or how to pay the water bill.

Use your brain.