Starting school hasn't bothered me at all, but this tooth has. I thought I was going to be the only mum not crying at the school gate, but now it doesn't matter because I'm about to have a kid whose tooth will be the same tooth showing when she smiles on her wedding day (assuming she wants to get married, that is), and when she gets her first job - hopefully not in that order.
And aside from this tiny tooth being a very obvious symbol that my baby is growing up, I'm now faced with what to do with it.
Some horrendous ideas have been popping up on the internet and they make me feel quite sick: People are making "dolls" using the teeth.
Just no.
Since we had our girl, my husband has been given a lock of his hair from his first haircut. I think he tucked it away for sentimental reasons but I am kind of creeped out by a tuft of hair that has been in a cupboard for 40 years.
It's the kind of thing that only really means something to a mother. I don't want 40-year-old hair in my cupboard, I don't even want my own kids' hair. Why not keep their toenail and fingernail clippings too? Ugh!
So I don't really want to keep my girl's teeth, nor do I want them to be made into a creepy doll that is clearly going to come out in the night and murder my entire family.
But I don't want to throw them out either. This tiny, perfectly white little tooth is a symbol.
When it popped through at six months old it was the first sign she was no longer a newborn.
It holds memories of those hours spent dealing with a miserable first-born, not knowing what to do, not knowing what the problem was in those very early months of parenthood - and it's a sign of how far we've come since.
And, just like the clothes she'd outgrown but I had trouble parting with when I found out her younger sibling was a boy and wouldn't be wearing them, this tooth is mostly a symbol of a fact parents find hard to accept: We don't have a baby girl anymore.
In throwing it out, I'm throwing out a piece of her, and I can't do that.