She looks really uncomfortable. Is it such a good idea to put an inexperienced, large rider on such a young horse?
That's the problem :) She's not an inexperienced rider. She's been riding for years, rides endurance and rides English and Western in shows. She's just a lousy rider :)
Oh come on.... any of us can take a bad picture, I'd be making that face just from the heat there.
And she's no bigger than the men who have been breaking and riding horses for us since before polite women did such things :~)
Let's be fair here.