If she can't avoid a stationary object, she's not safe on the road yet.
As you say, it's up to her parents, but circumstantial evidence suggests they think the same as me, as she wasn't on the road.
By the way, I'm one of those people everyone likes to hate: a non-driver. Yep, I only walk and cycle. I walk far more than I cycle, and easily achieve my 10,000 steps a day, just walking on pavements, and I say I'd rather see her on the pavement. I get very annoyed by adult commuter cyclists on the pavement, but not the wobbly under-13s.
As a cyclist, it terrifies me seeing the 10-13 year old age group on the roads. I see them trying to be all adult on the roads like big boys and girls when they can't hold a straight line yet, have no idea when they do and don't have right of way, and have sod-all idea what to do with a roundabout.
If you wouldn't merrily wave your 12 year old off in a fully MOT'd Volvo with airbags and fully-functioning seat belt, don't send them out on to the public roads without checking they can actually cycle safely.