Nothing to do with riding, but since people are talking about making sidesaddle habits, a sewing tip:
Pre-wash EVERYTHING you can that you’re using in the garment (apron, jacket) in the way you’d like to be able to launder the finished item, BEFORE cutting into it at all. With some fabrics that fray easily, you might have to just run the cut ends through the sewing machine or otherwise ‘finish’ the cut ends so they don’t fray on you. Likewise some interfacing isn’t really washable on it’s own, so - you have to play it by ear a little, but the lining fabric and the ‘fashion’/outer fabric should certainly be able to be cleaned no problems before doing anything else.
(This includes, btw, if you’re planning on dry cleaning. Just take the lengths of fabric to the dry cleaners. If they can do curtains and things of that nature, you should be okay with having the fabric washed.)
The idea is that by pre-washing/cleaning, you give the fabrics a chance to shrink, stretch, do whatever they’re going to do when being washed and dried BEFORE you cut them to shape and start sewing things together, so that when you wash/clean the finished item, you don’t end up with it bunching or puckering weirdly because it turns out that the lining fabric you used shrank a lot more than everything else.
(It is kind of a PITA to manage huge long pieces of uncut fabric, but particularly for something like a garment to be worn riding fairly frequently, it’s definitely worth knowing that you CAN clean the thing and have it come out looking the way it should.)