Imogen McSmith: I grew up with you, Harry, but it's over

One evening, when I was six years old, my older brother and I settled down in the garden, and our mum read to us about the boy with the lightening-bolt scar. I was enchanted. From then on, J K Rowling became my absolute hero, and I spent almost every waking hour talking about Harry Potter.

I was always a bit of a bookworm, but many of the kids at school with me would claim that the Harry Potter series were the only books they had ever read. Even my book-phobic older brother read a few of them for himself when we had grown out of being read to. When we were six or seven, my friends and I loved to play Harry Potter, inventing our own adventures around Hogwarts. It wasn't just a book, it was an obsession.

I would amuse my father by insisting on reading them over and over again, and I blush to remember how, at the age of eight, I wrote myself a letter of acceptance, as if written from Hogwarts school.

Growing up with Harry was not without its ups and downs. I remember, for example, being very irritated by Ron Weasley in the sixth book, published five years ago, when I was 14. I desperately wanted him to get together with Hermione. Surely the whole world did, particularly as Harry had had his first kiss and Ron still hadn't had any romantic encounters. But then Ron started going out with Lavender Brown. If Hermione was hurt, I was scandalised.

Harry Potter has stayed with me (although I'd like to think I would view such betrayal with more equanimity now). I have matured. These days, at university, a major pastime is playing Harry Potter drinking games. My favourite one involves compiling a Harry Potter quiz. Those who fail to answer questions correctly have to take a swig of something disgusting. The punishments I most enjoy inflicting are vodka with pesto and ketchup and toothpaste.

I also stubbornly refused to have anything to do with the Twilight series. I wanted to remain loyal to Harry Potter.

When I began to learn Latin at secondary school, it was bizarre how many of the words I recognised from Harry Potter, and it quickly became one of my favourite subjects. I am now studying Classics at university, the same subject that Rowling herself took, and I'm not sure I can entirely truthfully say the fact didn't influence my choice.

Most people, I suspect, had mixed feelings about the final book, and I certainly did. When my friends and I were queuing excitedly at midnight to buy the last book, after having a Harry Potter 7 party, I tipsily said to my best friend, "How is life going to go on after Harry Potter has ended?!" I was only half-joking, and I feel the same way about the film series coming to an end.

In a way, their conclusion will mark an end to my childhood, particularly as the final film comes out in the same month I will turn 20. We have grown up with Harry. We were young enough to be enthralled by the pure magic and fun of the first book, and, as the series got grittier, we were old enough to appreciate the darker, more political side of the story.

Harry, you were a huge part of my childhood, and I'll always be grateful. Now I need to go my own way, but I'll be back. If I have children of my own, how could I not be?