When does Toddlerhood start?

This week Cora has started walking.  It has been six weeks since she took those first unsteady steps between two adults she trusts, but only six days since she started really walking.  There were weeks of nervous steps between people or furniture but this week she has decided she is happier on foot and has barely crawled since she made the decision.  She still looks a little wobbly, still falls over a lot, especially on uneven surfaces and she still looks immensely proud of every step she takes.

With eleven little white teeth filling Cora's mouth, her smile looks much older than her brothers at the same age.  Her hair is just about long enough to make little pigtails and she loves playing peekaboo.  From the outside Cora looks very much like a toddler.

When she curls up in my lap for milk, her eyelashes fluttering as she slowly falls into a land of dreams, her chubby little hands resting delicately on my top, her legs tucked up so that she is fully encased in my arms, her chest rising and falling next to mine, she seems so small still, a baby.

At 13 months Cora isn't talking yet but she is definitely understanding more and more.  She is trying to master a spoon and fork with varying success and she is getting pretty good at climbing.  Sleep is still a challenge and she is far from sleeping 'through the night'. She eats food on her terms and breastfeeds regularly.  It feels like she swaps between being a baby and a toddler several times a day and I think we are now in that transitional phase.

Each of my babies have been so different at this same age, some definitely entering the world of toddlerhood, others were definitely still babies.  I think the baby / toddler divide is determined more by milestones than age, and I am sad that my last baby is leaving behind another stage, that I will never have a little baby of my own again.  I love this little toddler that she is becoming though, so determined, so funny, so inquisitive.  

Where do you think the divide between baby and toddler lies?