15 month old

[MortifiedAdams]

Sitting on the potty fully dressed and saying 'wee wee'.... Is she just playing or does she know what 'wee wee' and the potty actually are?

Too early to train yet, right?

Too early!! Let her try and sit on it when she likes but that's as much as if go for at the moment.

I'd say that she probably does know that she is going. But perhaps won't be able to tell before she is doing it yet? DD was about that age when she started saying wee and we're pretty sure it was when she was actually weeing. She's now 18 mo and asks to go for a wee, she has about a 75% success rate (we are using pull ups as she does not want to wear a nappy but has no clue about poos yet, we have persuaded her that pull ups are pants and she still asks to go for a wee when wearing them).
Anyway, my point was that she probably isn't ready to start proper training just yet, but it's great that she's obviously getting an awareness, so you'll probably be able to start in a few months
Is she willing to sit on a toilet/potty? As there's not harm in popping her on every so often, such as before a bath, or when you go to the toilet