I have been practising looking cool, calm and confident in the mirror. So far, the best I can come up with is appearing bad-tempered or terrified. I read in the TES that I should present a credible image to fashion-conscious teenagers, so I am worried that my trousers are the wrong shape and my boots are just so last year.

The trouble is, I have a terrible case of impostor syndrome. I am still a civilian for goodness sake. I will be found out.

I have recurring visions of walking into the wrong classroom, spilling coffee over GCSE coursework or standing in front of a class and realising I still have my dressing gown on. There is also a group of people out there who will be on this course with me and I don’t yet know any of them. What if they don’t like me? What if no one talks to me?

Last week, I tried to reassure myself I at least knew my subject. All of a sudden, my full set of Jilly Coopers seemed to take up an entire shelf and the Penguin classics were entirely eclipsed by Terry Pratchett. In the library, I looked briefly at the education section, realised that I cannot tell an adjective from my armpit and went to have tea and cake instead.

My anxiety got worse when I collected my son from after-school club. I met his new teacher in the car park carrying a crate overflowing with files and books. Is this what is in store for me?

Ever since I thought of becoming a teacher, people have been telling me it is the ideal career for a single parent with a young child. I will, apparently, have the holidays free and finish at the same time as my son. I smile politely when I hear this, thinking of the nightmare of organising after-school club, holiday play schemes and before-school care - this last one relying on the goodwill of neighbours and friends.

What if every contingency plan goes pear-shaped on the same day? Usual single-parent guilt kicks in again. I have promised my son that we will spend Sundays together this year but, apart from that, I worry that I may hardly see him.

Then I remember why I am doing it. All the stuff I said at my interview was true (well, most of it - the bit about being really organised was mighty suspicious - my filing system involves throwing stuff in a big box until “later”). But I have a passionate belief in the value of education, I love my subject and am really looking forward to learning how to teach. To my friends’ amazement (and mine), my carefully developed cynicism has been put on hold. I am genuinely bright-eyed and enthusiastic. I’ll be fine, I tell myself. It will all be fine, just as long as my trousers are the right shape and I get some shoes that make me look taller.

Charlotte Read finished an MA at Oxford Brookes University last year. She is now a PGCE student at Oxford University