It begins when she’s seven. Her father brings home a desktop computer; he shows her that if she types “cats” into a search engine she will be met with the sight of “hundreds of kittens. Millions of kittens.” The same goes for horses. And ponies. And unicorns. “Images blink into existence”, as though the machine is “listening to [her]”. This seems innocent enough. As does the virtual pet website she begins to spend time on and the AI chatbot she has funny conversations with – “why did the chicken cross the road?” Less innocent, perhaps, is the way Google autofills with suggestions for searches, the way she starts to sit absent-mindedly, clicking and scrolling alone every evening after school, until the computer becomes an extension of her. Less innocent is the way she eventually no longer forms “conscious intents” and begins instead to “simply act”.

When I’ve been summarising This Is How You Remember It to friends, this is the point at which they begin to squirm. “No,” one said, and repeated the phrase as though my going on would be the cruellest form of torture. “No. No. No. No.”

I think I was only slightly older than Prasifka’s narrator when my poor mother found my internet history, stored on a desktop computer I should never have had access to. Shame, self-preservation and time have protected me from the memory of whatever she said to me that day, but two decades later I have not forgotten the aftermath, the heartbreak in her voice when she finally calmed down. “If you wanted to know about sex,” she told me, “I could have bought you some books about it.”

I gather, from my friends’ reactions to synopses of Prasifka’s novel, that mine was not an uncommon experience. Prasifka herself seems to know this. Her narrator is a distinct being with homework, relationships and hurdles of her own, yet the book is delivered from her point of view in the second person – we know her only as “You”, an ingenious move that often breaks the membrane between fiction and experience. Over the years, “You” progresses from anxious snatches of internet porn to dirty talk with strangers in chatrooms, and videos that are “pretty hardcore”. “The first time you’d seen a blowjob,” she recounts, “[i]t had made you gag … Last week you’d seen a video of a man actually pissing on a woman and it felt normal.” At a school disco, “You” faces a classmate’s erect penis and says “Let me go” – but, “you’ve watched videos where this happened … So you sink back into yourself. You know how you’re supposed to act.” It is the first and least horrifying of many such moments.

In her 2021 collection of essays, The Right to Sex, philosopher and academic Amia Srinivasan expresses surprise at her students’ lack of arousal in the face of internet porn; their accounts of using it “to ‘learn’, to ‘have a kind of idea’, to ‘pick up things’”. This Is How You Remember It renders this education in real time, eschewing shock for insight. How could we be surprised? Sex is not the only facet of life warped by internet technology. Friendships are mediated through instant-messaging services, carefully shaped identities on social media “carry over into real life”, dating apps turn the narrator into “someone pre-approved by Google’s algorithm”.

At regular intervals, Prasifka offers us counterpoints to this developmental process that throw its wretched consequences into relief. Some work better than others. Lorcan, a slow-burning love interest, is distinguished by his lack of attachment to the computers or phones that penetrate the life of his peers. This makes him fundamentally “good”, yet it’s not clear how he manages to achieve this level of technological purity – why the internet exerts no pull on him, as it does on everyone else. More compelling in its argument for a tech-free life is a beach our narrator returns to regularly over the course of her life. Prasifka patiently frames and reframes this setting through some sort of screen (a camcorder, an Instagram post) several times over, so that when it finally appears simply as “montbretia … in flower”, a smell reminiscent of “the ocean, and sun cream and wet grass”, we feel sincere relief at apprehending it without a camera.

There are some other uneven moments, a few unnaturally gnomic expressions of suddenly retrospective regret that fail to lend the book any kind of gravitas it doesn’t already achieve on its own (“You haven’t yet learnt to recognise the red flags, but you will”, reads one example). There is occasionally the sense that the novel neglects to mention the internet’s potential to foster, even for teenagers, community, or positive modes of identification. Frankly, having pointed all of this out, I don’t care. I don’t usually write book reviews in the first person. Rightly or wrongly, I affect a critical persona that suggests some form of objectivity. But if you, like me, are a woman of a certain age, reading Prasifka’s book hurts. It hurts too straightforwardly to mask the pain with complaints about lapses in form. It is very possible that parts of This Is How You Remember It happened to you, too, at seven, eight, nine, 10 years old. You didn’t have the distance, or maturity, or knowledge to avoid it.

Towards the end, we find “You” thinking over the events of her life. She wants “so badly to recognise them as wrong, as perverse, as abusive, but it’s so hard to recognise it when [she] didn’t feel it at the time”. If only my mother and I had had this book to hand all those years ago. It is an essential document. I wish it wasn’t. I’m so glad it exists.

• This Is How You Remember It by Catherine Prasifka is published by Canongate (£16.99). To support the Guardian and Observer, order your copy at guardianbookshop.com