Being a teaching assistant has made me feel more alive than ever – and even more determined to become a teacher

"Frankly, I question your sanity going into teaching," a former boss said, in response to my request for a reference for my part-time PGCE application.

I can't say I blame him. On my first day as teaching assistant (TA) at a local primary school (a job I have taken to complement my PGCE and bring in a little cash) I encountered two news reports about miserable and overworked teaching staff; one teacher in tears; a five-year old hurling physical and verbal abuse at a member of staff; and an IT system that was cutting edge back in my university days in the early 1990s.

So why have I given up a fairly lucrative job as a freelance editor to lash myself to an underfunded state school system?

It sounds ludicrously idealistic and naive – I can almost feel the eye rolls – but I want to make a difference. After years of feeling like I've been spinning the hamster wheel to line someone else's pocket, I have an almost primal urge to see, feel, hear and touch the effects of a day's work.

I'm not so stupid as to vocalise any of this Pollyanna poppycock in the staffroom. I keep my head down when the exasperated diatribes spill out during tea breaks. I hear endless complaints about bad parenting, too much screen time, not enough discipline, too much assessment/paperwork/planning. And so it goes.

But I have also noticed something extraordinary, that I suspect only someone who has worked outside teaching would notice. When the staffroom door closes behind each and every one of those people, they head off to the children with their shoulders back and smiles on their faces, determined that they will get the best out of even the most difficult pupils. Their inner idealists come out – pushing up out of the mountain of paperwork, marking and assessments.

When my two boys were in primary school I was desperate to be a fly on the wall. Now I am – and what a revealing, terrifying, illuminating, frustrating and hilarious experience it has turned out to be. I've witnessed a heartstopping choking incident, a broken arm in the playground and I've almost been reduced to tears when told off (very publicly) for giving a child's tummy ache the time of day. "What are you doing? Don't worry about him, he's a class A wuss."

I am still at a complete loss as to when the children can and can't go to the toilet or have a drink – it appears to be entirely at the mercy of the teacher's mood. "Can I have a drink?" asks a student. A reasonable request, I thought, he's thirsty. "Why are you over there?" bellows the teacher. "You had plenty of time to drink at break." The child in question and I stare at each other across the classroom silently hating her for humiliating us both in front of the class.

I've wiped poo off the toilet walls, had daily battles with a photocopier that I swear sees me coming and I've filled in enough bumped head forms to furnish Dostoyevsky with a lifetime's supply of manuscript paper. I've been kicked and I've been hugged. I greet them at the door every day, I hear about their sleepovers, their pet snails and their pet hates. I love it.

I'm still struggling with behaviour management – there seems to be an unwritten rule that the children just about hold it together for teachers, then release all the pent up tension of being institutionalised for six hours when it comes to TA time.

But I'm just about getting used to being handed a lesson to teach to 15 of the most needy and vulnerable children in the school with a few seconds' notice. I am sincerely glad that I chose to enter the profession in my mid-forties – my younger self would not have had the confidence, resilience and determination to cope with the behaviour of children (and staff) each day.

Working in a school has made me feel more awake and alive than ever before – and even more determined to qualify as a teacher. As a TA by day and a PGCE student by night, I have never learned so much so fast. On day one I struggled to remember the names of the three children in a guided reading group. Now, I know the name – and I've got the number – of almost every child in the school. I could probably even tell you what they had for breakfast.

"Don't give up the day job," laughed a TA with decades of experience as yet another phonics session dissolved into chaos. "Too late," I say. " I already have."