Cute story. I like your take on a young Remus, I've never seen it done before.
'Remus, you can ride the horse a bit later. It's time to eat,' his father said lifting his son off the saddle. 'I'll show you how to de-saddle him after dinner.' (quote from previous chapter)
Just a note, if you're going to continue with the horse, you may wish to brush up on some of your terms just to add to the authenticity. For example, one would say "unsaddle" or "untack" instead of "de-saddle". Just thought I'd point it out, I'm really picky about that stuff (as I am a rider)