I know the families well, in fact one girl is family, and these are two mature, responsible young ladies who are wanting to spend their summer vacation on my little farm. They both were here a lot last summer and we never had any issues.
I think it's a great way for kids to earn saddle time, if for no other reason than that's how I "paid" for my lessons when I was their age.
The 13 year old is my sister-in-law and has no riding experience, but my in-laws did own horses for years before she was born, so they're familiar with being around horses.
The 12 year old (will be 13 very soon) lives next door and has a bit of trail riding experience with church groups. Her parents also owned horses before she was born.
I have a pretty good outline of what I would want each lesson to entail to keep them both safe and satisfied through out the break from school. And I have more than enough age-appropriate chores they can do, so I'm thrilled to have the offer of help.
I've told their parents that the girls will need boots with a heel and a helmet before they get in the saddle.
Is there anything else I need to keep in mind?