This week, roughly 600,000 11-year-olds will start secondary education. Eager young minds, looking forward to making the step up to big school – and taking their first tentative steps towards adulthood.

Brand new blazers, sharpened pencils, shiny new shoes. New beginning, new opportunities, new friends. All very exciting. And also rather terrifying.

Not for the kids, you understand. For the parents.

Because there’s nothing more stress-inducing than sending your baby out into the big, bad world of secondary education. I should know. It’s been a long summer, and I’m still not sure I’ve quite recovered from the rollercoaster that was Year 7.

Don’t get me wrong: nothing catastrophic happened. My daughter Beatrice is at a brilliant school, with fantastic teachers. She’s met a lovely bunch of new friends, and academically she’s never been stronger. She’s happy, confident, healthy and full of beans. No, it’s me who’s a wreck.

No one tells you about this bit when you have children. There are endless manuals on the early years, about feeding and behaviour and how to encourage the young brain. But what no one bothers to mention is that the hard stuff doesn’t come until later – much later.

Part of it, I guess, is coming to terms with the fact your child is pulling away from you; but it’s also the realisation that, however grown-up they may think they are, they are still hugely vulnerable, both physically and emotionally.

The human 11-year-old is not quite child, not quite adult: a creature in flux. But where once this transformation happened within a relatively self-contained environment, now it takes place in the full glare of technology, with all its attendant pros and cons.

The trickiest social situation I had to deal with at my daughter’s age was the school disco; today’s kids exist in a technologically-induced minefield.

So, what to expect? It’s about managed risk and learning when to step aside and when to step in. It’s watching them make mistakes – often the same ones you made – and resisting the urge to micro-manage every move. It’s understanding that theory doesn’t always translate into practice.

If I had to sum it up I’d say that it’s a bit like childbirth: you have to experience it before you can comprehend the reality. That said, forewarned is forearmed. So here, in the interests of the sanity of all you Year 7 parents out there, is what I’ve learned. Good luck.

1. Do not send your child off in a blazer three sizes too large. You may think they look adorable. But, as my daughter reminded me the other day when I tried to persuade her to buy the larger size in the interests of economy, ‘it will crush my social identity’.

Also, she has asked me to add the following: ‘Do not lie to your child about how their first day will be. Do not say “it will be fine and you will make lots of lovely new friends”. It won’t. The Year 8s will make sure of that.’

2. You can no longer control what your child eats. The school will tell you it has a healthy menu, and probably does. But unless you happen to have one of those saintly children who do what they’re told when no one in authority is watching, the chances of them selecting the healthy veg option are slim.

It was only after secret discussions with one of my daughter’s more sensible friends that I discovered that for the first term – free to make her own lunch choices – she had effectively lived off jelly and strawberry laces. No wonder she was tired and teary. Also, beware the after-school snack-fest. Chips, fried chicken, sweets, crisps. It’s a nutritional minefield.

3. Public transport is fine in principle, terrifying in practice. You’ve rehearsed the bus journey to and from school several times; you both know the route. But what you haven’t factored in are all the unpredictables.

From personal experience, in no particular order: a) Getting the right train or bus – only going in the wrong direction; b) Being invited by the cool kids to walk with them to the station, accepting and then ending up stranded on an unfamiliar platform with no idea which way to go next; c) Being refused entry to the bus because you’ve lost your travel card.

4. Instagram and Snapchat. If you do only one thing, take a crash course in both. Mine had never been on either, not having had a mobile phone before.

Within weeks of starting school she was on both, with all the attendant anxieties. Of course, you can ban them – but if you do so, you are effectively condemning your child to social Siberia. Best to accept them as inevitable – and set strict rules around their use. This means getting your own accounts and making sure you follow your child and your child follows you. Make this a condition of use, and you will be able to keep a discreet eye on their activity, while also reserving the right to shut down anything you think is inappropriate.

5. Be strict about the amount of access your child has to their phone. I didn’t realise this at first, but these devices are incredibly emotionally intrusive, and can be extremely anxiety-inducing. Not only that, they distract from the whole purpose of secondary school, which is to learn stuff.

Yet they are extremely useful in other respects, especially if your child is making their way home on their own. My rule is simple: I take the phone off her when she walks through the door at 4pm, and she doesn’t get it back until the following morning when she leaves for school. At weekends, hours of use are restricted and have to be earned.

6. Vocab. It is not a play date. I repeat: It is not a play date. It is a ‘hanging out’. There are distinct tribes, too. The ‘smarts’. The ‘gangsters’ (they can dance, they have six-packs, they wear baggy clothes). There’s the ‘pretty populars’ – see Netflix’s Mean Girls. And then there are the ‘cute and kind’ – basically the children all the parents like. At the start of Year 7 everyone is in the ‘cute and kind’ category. Then they fragment.

7. Your child will be exhausted. This is because a) they have to move between classes, so they’re just running around a lot more and b) because they have to get to know so many teachers. My daughter spent the first term too scared to go to the loo in case she was late for a lesson.

There is just so much to remember: timetables, exercise books, pens, pencils, protractors. You will have to be on top of this for the first few weeks, otherwise your child will end up in a terrible mess, and get loads of detentions. My advice is to purchase a small filing cabinet and keep every subject clearly labelled in a separate drawer.

8. Get to know your child’s teachers. There is a general assumption that parental involvement slacks off in secondary school.

If anything, though, I’ve found it helps to maintain contact. Teachers often know more about your child’s state of mind than you do.

This is particularly helpful if your child is going through a rough patch, because you might find they withdraw a little and stop talking to you.

A chat with a wise teacher can dissolve a lot of emotional knots.

Believe you me, if I’d had the nous to institute these rules at the start of Year 7, I would have saved myself an awful lot of tears.