I think you're right on track. When I first got my son started I got him a CZ Scout, thinking I could get a full size stock for it eventually and maybe even rebarrel
He got kind of sentimental with it though and didn't want to change it. So, for his next rifle, I got him a CZ457, but immediately put it in a chassis so that it can grow with him.
So, I think you starting with an Origin is the right move.
The XLR chassis is a great chassis that has an incredible amount of LOP adjustment. I'd be looking there to get started, and it can grow with her forever.