Diary of a Primary School Mum: It's posh, snooty and perfect for our youngest'

Good news came yesterday. At least it seemed that way until somebody said, "oh dear, now you're in a pickle." When I told my best friend about this piece of luck she was quite taken aback. "Why on earth would you want THAT?" she gasped, as if "THAT" was a one-way third class train ticket from London to Siberia. Despite no plans to either visit the wilderness or exile myself, there are still nerves about feeling excommunicated because the good news is this: Claire and Oliver's younger sister sat for a selective, private school and against the odds she was offered a place.

"You can't have two of your kids in the local state primary and send your third to a posh, snooty place. It's not right," said someone I thought was a friend. "What about the impracticalities of the school run," another pal pointed out. For every person who considers this idea lunacy, I've canvassed another in a bid for support. Sweetly, after much arm-twisting, a couple of reassuring "well, it's not what I would have done, but if it makes you happy and you think it's right for your children, that's all that matters", were received.

Private versus state has been a major dilemma since the twins' birth. All parents want the best for their children, hence the appeal of smaller class sizes and superior facilities. The majority of good, selective schools, however, are single sex and splitting up my boy/girl pair was never an option. So the decision was made to keep Claire and Oliver together and no regrets on that front. Their league-topping, local primary has done them proud: they're happy, thriving and making excellent progress. Why, then, not keep things simple and send their sister there too?

It's a confusing pickle, not helped by living with a bunch of alter-egos. My daughter has donned an eye-patch and morphed into Claire the cutlass, my son into Oliver the 'Orrible, characterization inspired by Miss Perry's current pirate theme. The last fortnight or so Reception have been plotting treasure maps, hunting gold, sending messages in bottles and making telescopes. It's fancy dress Friday. Pupils arrive sporting skulls, crossbones and hook hands and the role-play doesn't end with the costumes. "Shiver me timbers," I overhear one boy say. "What shall we do with the drunken sailor?" roars another. "Make him walk the plank," squeals Claire.

Signing the acceptance letter for the private school had seemed a formality, especially when my anti-private education husband was as euphoric as me on receipt of our "good news".

But as I watch pint-size Captain Blackbeard's swashbuckling, my certainty wavers. This primary has a relaxed environment full of happy children. Will they play pirates at the posh school, will they feel this nurtured, or will the pressure lead to hours of therapy later on in life? I don't want to deprive my youngest of a carefree childhood, nor can I deny her a wonderful opportunity. The decision is harder than expected.

Loitering near the posh school it's make-your-mind-up time. Inside its sports centre a pupil holds a door open, making excellent eye contact. Uniformed girls chatter down the street, vibrant and intelligent. Trills of woodwind instruments seep through the walls of the pre-preparatory. There are grounds, there are tennis courts, there's only 16 to a class and my daughter could stay here until she is 18.

One size does not fit all and my youngest is already excluded from the twins' relationship. This could help her forge her own identity instead of forever being in their shadow. Bank balance aside, not such a hard decision after all.