Good for her.
700 rent on 12k purchase is a great ROI, depending on a few variables (any back taxes or liens needed to be paid off, since they bought at auction, and cost to fix up, since they said it was trashed).
Also, I laughed at the last picture (Willow + tenants). Don't you think those tenants would be embarrassed that their landlord is a 14 year old girl?
Sounds like the mom really knows what she's doing though. Many Realtors aren't actually doing real estate themselves, but her mom being smart enough to get a place, fix it, and rent it out is smart.