PGT/Park girl (8)/Older/Yes/Go up and ask why she's here alone
You plan out a way to approach her. Showing concern for why she's here alone sounds like a good foot to start off on. After all, a kid her age should be suspicious if an adult does NOT approach from a position like that. Adults make things difficult for kids, always asking them to follow the rules. Showing that you are the same should make her drop her guard a little.
"Hey there, I'm sorry but... can I ask you something? It's not good for you to be here by yourself, where are your parents?"
"Ah... umm..." The girl responds, looking a little flustered. She ultimately does not answer, but she also does not seem to look all that suspicious of you. Seems this was the right approach.
You heave a big sigh and approach closer to her, climbing up onto the jungle-gym like climbing structure with her. "Look, it's dangerous for a little kid like you to be by yourself at the park. You need an adult with you." You breath another sigh, you are taking a horrible risk of that spooking her off, but if this works then it should blow past a lot of her defenses. "Alright, I guess I won't bother you about it too much, I can probably see if somebody comes and tries to kidnap you or something. Well, can you tell me your name?"
She looks down at the ground through the bars of the climbing structure as you climb up to the same level as her. "Umm... Amilia." She says.
"Amilia? My name's Larry. How old are you Amilia?"
"Umm... I'm eight."
"Yeah? So then, why are you here at the park alone?"
"Mmm..." She went silent again.
Has been told not to talk to strangers. (Doesn't take it completely to heart, but will use it as an excuse if you make her uncomfortable.)
Reasonable level of awareness she shouldn't let someone see or touch her privates.
Knows boys have something called a penis, hasn't seen one or a picture of one, but has something of an idea it sticks up from the privates area. Is not aware of her own vagina.
Pregnant women. They get pregnant from daddies. (Not certain how.)
Something you're not supposed to talk about? (Has heard the word, but mother refused to give details.)
Does not know, has never heard the word.
Is not supposed to be at the park, will not tell mother about things that happen here so long as it's nothing that distresses her too much. (Will only talk if you do something that will distress her a fair bit more than getting in trouble with her mom for going to the park.)
Has a "slow to warm up" (AKA "shy") personality, doesn't say a lot with new people. Also has relatively poor people skills.