I'm not sure what to say, so I say "great."

Or grand. Or something equally witty and incisive. Inside, I'm assessing the damage.

She apparently knows what a penis is, but as far as anything else is concerned, we seem to be maintaining a course of all at sea. I was 11 before I knew what a penis was. I remember this with absolute accuracy because I was in the Gaeltacht at the time and I made a fool of myself for thinking it was a badly pronounced piano player. My daughter is more than two years ahead of me. I blame co-education, the internet and The Simpsons.

Of course, I wouldn't be in a position to blame anyone at all if she didn't keep offering me up these nuggets of misinformation that "they" are gradually amassing. As far as I'm aware, nobody else's daughter tells their mother that they're looking up tantalising words in the dictionary, that they keep dreaming about Daniel Radcliffe or that a certain boy makes them feel mushy inside. But for some reason, The Small Girl has yet to find her off switch. Maybe I should feel privileged, but frankly, I'm just mortified.

Here I am gearing up for a decade or so of coughing over key moments in television dramas and avoiding all eye contact . . . and there she is, poised at the brow of the rollercoaster and suggesting gleefully that I fasten my seatbelt.

I suppose it is around this point that parenthood stops being cute. "When is a cloud?" is just so much more endearing a question than "what is a period?" but one follows the other with a depressing inevitability. In our house, the Awkward Question came about a week ago, courtesy of the aforementioned Simpsons and a Jo Brand-style character who came on stage at a comedy gig and announced "I got my period today." "Oh my Lord!" exclaimed Marge, in the audience, while this Mom, at the sink, thought much the same thing and steeled herself for the aftershock.

I should state now that for my entire adult life, up to that point, I had assumed that I would be the kind of mother who deals in spades. Euphemisms had no part in my future plans where the difficult questions were concerned and as for lies . . .

frankly, I respected my children too much to ever insult them with storks and cabbage patches. So when, at approximately 7.10 last Tuesday night, The Small Girl asked me what a period was, I instantly and with absolute transparency told her that it meant some free time between classes in school. When she walked out of the room without another word it occurred to me that a) I'd let myself down, b) I'd let her down, and c) she probably already knows (possibly through the penis person).

So suddenly, this is where we're at.

Yesterday I was looking down at her in a little perspex cot, wondering how something so small could have made such a big impression on me and now, I'm getting ready to help equip her for a journey which, no matter how much she might want my company now, she must take without me. But for today, we still have precious moments. When I spoke to her on the phone from Venice at the weekend, she wanted to know if we'd been on a gondola. And then the smallest grown-up on the planet asked the inevitable follow-up: "And did you have a romantic?" Sometimes, I'm mad about that girl.

We did have a romantic, as it happened, in Venice, a city that defies description, logic and physics. It's also shockingly expensive . . . sitting down for a coffee and a beer in the afternoon sun in Piazza San Marco cost us 26 and, on the basis that half the world is starving, I'm too ashamed to tell you how much we paid for the gondola. On the plus side, once Disneyworld buys the city out in order to simultaneously save it and turn it into a theme park, I'm sure the rides will become much cheaper. On the down side, they're bound to put water guns on the Rialto bridge so that tourists can drench the gondolas as they pass beneath. Rainwear will of course become compulsory and you'll need to be this high to ride. In the meantime, go and see Venice now in its ridiculous magnificence, even if you do die at the prices.

Next, the phone phase!

Back home, the phone that has been out of order for three days is finally fixed and announces that we have seven messages. I dutifully open the diary and poise the pen, but all seven are for the kids (and feature wildly varying degrees of competence). I listen to them all and then put the pen down without making a single stroke. I really think we're on the cusp of the next phase of parenting. And something tells me that if we thought Venice was expensive, we ain't seen nothing yet.