I have been struggling with nearly the same issue. I have gotten back into riding after YEARS away, and my 12 year old son has also been riding for about the last year and loves it. I was looking, with the intention of getting one horse that we could both ride. However, lately I have switched my focus to getting one for each of us. The ones that would be good for him may be a little slow for my taste, but the biggest deciding factor for me is that if we only have 1, then only 1 of us can ride at once. We like to do trails, so it makes more sense at least for us, to have two. Whether that means leasing ,or buying, or whatever works out.