The most common signifiers of adulthood used to be getting a mortgage and gearing up for the midlife crisis. But who these days has the money for the former, or the time for the latter? Nowadays, the surest signs that you’ve reached maturity are an obsession with property magazines and a fascination with the quality of your sleep. Going by this criteria, I am more middle-aged than the most middle-aged sitcom dad ever (Darrin from Bewitched, who, Google informs me, was played by an actor five years younger than me when the show started. I am totally and definitely fine about this.)

I am fascinated with sleep – but nowhere near as fascinated as everyone else, it seems. I can hardly walk down the street without someone telling me about their latest sleep app, or reading an article about “good sleep hygiene”, or hearing how sleep deprivation is the health equivalent of chaining 40 Benson & Hedges a day, and of course how tired – so very, very tired – everyone is, because they didn’t get their requisite eight hours last night.

How I laugh at this. I throw my head back and laugh the kind of full-throated cackle an evil genius makes right before he presses the red button that blows up the world. I have barely slept more than five hours a night since my daughter was born eight months ago, and there is something genuinely hilarious about this era of sleep obsession when you have a baby who refuses to let you sleep. It’s like living in a busted shack when everyone around you is banging on about the problems with their new basement extension. (I told you I was into property magazines.) “The truth about why you keep waking up at 3am” a doomy headline in this paper read recently. Is it because there’s a screaming baby in the cot next to your bed?

“God, I’m so tired,” I used to say when I was young and merrily childfree. Talking about how tired I was back then seemed to be a way of proving how deeply sensitive I was (too fragile to sleep) while simultaneously giving the impression that I led an extremely exciting social life (too fabulous to sleep). But I did genuinely think I was tired, and this is what I want to say to my twentysomething self and any other young person who is about to say how tired they are: you’re not.

If you have the energy to ascertain your tiredness and then talk about it, you’re not actually tired. You’re just thinking too much about yourself, which is what the entire wellness industry is based on, and which ultimately becomes detrimental because focusing too much on sleep will only exacerbate your sleeplessness. If anyone is worrying that they only got seven and a half hours’ sleep last night, allow me to reassure you: I have done interviews on three hours’ sleep, written articles on four hours, and I’m typing this after being woken three times in the night (as Amy Poehler says in her memoir, Yes Please, everything written by men and women with children under six should come with a “sleep-deprived” sticker on it). And I’m fine. OK, I can feel my brain cells self-cannibalising and have possibly given myself premature dementia: it took me two days last week to think of the word “gondola”. But I am still fine. Well, alive, anyway. I am definitely 100% alive.

So no, I don’t want to hear about how tired you are. But if you’re all having such trouble sleeping, how about if you take over the night shift with my baby? I’ll definitely sleep, and you and the baby can rave all night together. David Baddiel has said that the only thing that cured his insomnia was having kids, because they exhausted it out of him. Think of the money you could save on sleep apps, kids!

Awake at 4am, I fantasise about a time when my kids are teenagers and sleeping until midday, which means I’ll sleep until midday, too. Or perhaps not: older parents warn me that, while child-induced sleeplessness cures insomnia, it also breaks you, leaving you doomed for ever after to wake at 6am. So maybe we’ve got this parenting thing all wrong: just as twentysomething bodies are supposed to cope best with pregnancy and childbirth, perhaps fifty- and sixtysomething biorhythms work best with a baby’s sleeping patterns. Older friends and relatives could rise at 6am and take the baby out for a nice walk around the park, while we broken thirty- and fortysomethings could be left to get on with other things. Like sleeping. Strangely, none have yet accepted my suggestion, but they’re probably just mulling it over.

Last weekend I went away for a friend’s 40th, alone. We had dinner on the first night, and it was lovely, but I was impatient to get back to my hotel room where I knew the fun would really begin. Reader, I slept solidly for 11 hours. When I woke – naturally, as opposed to being woken – I nearly wept with happiness. The second night was a party and, giddy with freedom and an unaccustomed feeling of being well rested, I danced until the sky was light. The next day, I went home, and my husband, who had been looking after all three kids all weekend, asked how I was. I looked him right in the eyes and said, “God, I’m so tired.”