I thought - hoped - that I'd have more time, but it has happened.
My sweet little angel baby - the one I nicknamed 'Giggles', who'd wake up grinning, and would deliberately fall over just to make me laugh, has entered... (to be said in a deep, ominous voice) The Taaaaantruuuuum Zoooooone.
The warning signs had been there for a few weeks. Indignant squawks when a toy was taken off her, angry grunts when I didn't sort out her dinner quickly enough.
I chose not to see them because I wanted to cling on to my cuddly baby girl just a little bit longer. I couldn't bear to lose her to Toddlerhood.
But on Saturday my denial was shattered. I took her and Big Sis to the local soft play centre. One minute she was waddling about, happy as Larry (just who the hell is Larry, anyway?) left arm swinging like a pendulum.
Then I dared to remove a carton of apple juice that was about to spill everywhere... and all hell broke loose.
There was crying, there was kicking, there was collapsing on the floor and bucking like something out of The Exorcist. And then there was screaming, dear God, the screaming. Chances are you actually heard it - unless you live on the International Space Station.
Don't get me wrong, I'm not a tantrum virgin - Big Sis cranked out some doozies in her time. But this... this was another level again.
I couldn't pick her up - she was a crazed, freakishly strong, head-butting machine - and when I put her down she flailed so violently I worried she'd seriously hurt herself.
All the other Mums were doing that thing where they pretended not to notice the screeching, purple-faced child writhing on the floor by their feet, but I caught the occasional sympathetic glance. One lovely lady, bless her, even tried to distract Lil Sis, and jolly her out of her tantrum - but she way too far gone.
Why didn't you just leave? I hear you ask. Because if I'd tried to pull Big Sis away from the soft play I would have had TWO wildly tantrumming pre-schoolers to deal with.
Finally I took Lil Sis into the cushion room, set her down, cleared a path around her, and just let her go. And she went. For an entire hour. Not on and off, and occasionally stopping for air - 60 solid minutes of screaming, until she collapsed in my arms, her little body hitching with exhausted sobs. Then she slept, like a rock, for the next 90 minutes.
Then she woke up, grinned, clambered off my lap, and toodled off to play - as if nothing had happened. Until that next inevitable trip into... The Taaaaantruuuuum Zoooooone. Yes, OK, I'll shut up now.