@gittonsxv
IIRC Pinkie Pie said she was Mascara’s sister? Which granted doesn’t mean she isn’t from canterlot since I recall their grandma once being a teacher in canterlot.
IMO I think it’s more likely a case of a small child(filly) being…well…childish.
This filly just grinds my gears, but i think she’s supposed to do that. that said one anon acedently blows up her house from a spider i don’t think she’ll want him any more.