As a "teenager", I definitely was not a child. As a teenager, everything was new. And more often than not unexpected. What had changed?
Primary school to secondary school. Learning basic skills (reading, writing, arithmetic) to the more academic (History, Biology, Mathematics, Geography, French etc) . Independence, often fought for. Curiosity. Cigarettes, alcohol, cannabis, music (I was 15 when "Anarchy in the UK" hit the streets), "rebellion" against my parents' "norms". Puberty and consciousness of sex and anxiously wanting it but never "doing" it. Underage drinking on Friday and Saturday nights, Saturday and holiday job - the boss, Kate, was formidable but took me (hung-over) at 6:30 am under her wing.
Consciousness that I am "me", that I am "Angus". That I have an identity. That I am unique.
I cannot imagine my parents' generation when you could be in the factory from 14, or my grandparents' generation when it was even younger; Where I'm talking from, whether you are male or female, since year dot you may be working, and you may be a parent as soon as you hit puberty and have to be responsible for someone else. You are an adult.
And that is perhaps an important difference between childhood and adulthood. However, in the "developed world" I was not, yet, considered to be useful, I was not yet somehow adult. I was in a limbo between child and adulthood that has become known as "teenage". So I want to stop using "teenage" now and talk about young adults.
What else changed?
Learning I might die?
But for 2200 people per year (just) in the U.K. that is part of the above formula, of being a young adult.
Rob, in Siblings II, wonders what Fergus (aged 7) understands about his leukaemia and concludes "not much", the treatment is something to be got through. Kezia has even less understanding.
As a young adult, just when you are learning the ropes of being adult, learning about sex, birth and death and much else, then learning your own mortality, understanding that you may die and soon, must be pretty rough.
Lucia and H. and Josie Grove understand.