This is a vinyl window. Only the trim on the right side of the window would actually be in the shower.

Then your separate applied waterproofing membrane under the tile has to integrate properly with the vinyl of the window. Windows are not designed to be waterproof from the interior. The detailing of all of the waterproofing is a big extra step that has to happen. Or you get leaks and rot inside your walls. And your trim can not be wood. It must be sonething like Fypon.

For when you get your new shower, you'll need stainless steel rod flanges for your shower rod. Try to find one that is a full round an another that is a "U" shape so you can remove the shower rod as needed. I've found them both at WalMart (less expensive) and at the local big box building supply stores.

https://www.richelieu.com/us/en/category/builders-hardware/tubular-hardware-for-glass-railing-handrail-and-footrail-in-stainless-steel-and-brass/round-square-surface-handrails-with-components/wall-flange-for-round-handrail/stainless-steel-round-tubing-wall-mount-flange/1209432

https://www.walmart.com/ip/1-1-Dia-Stainless-Steel-Closet-Rod-Bracket-Flange-Holder-Pole-4pcs/672498555

If waterproofing the window is such a huge project, you might consider swapping out the window for a narrower one instead.

We have the same setup, except with a wood window. The window is trimmed properly with wood moulding (original to the 100+-year-old window/house), and then the tile just runs around it. It looks fine and we have not had any issues with water. However, the trim is painted with oil-based paint (no longer readily available where we live) and then the edges of the wood where they meet the tile are caulked so it is pretty well sealed. The shower has been set up that way for at least 60 years, possibly longer. We have a curved shower rod (mounted to the top window moulding) to clear the window.

Poor lighting, but will probably give you the gist of it:

This looks like it is at the opposite end from the showerhead? I think that the issues with waterproofing are a bit less critical as it will be little hit with water. I would still want to have it fully waterproofed behind the trim and use vinyl trim. I would also probably make sure that the sill had a slight slope towards the tub in case water was to get onto the sill.

Thanks, everyone! Yes, this is the opposite end of the shower head. Very little water hits the far wall, so I'm not too concerned about it, but will take the advice to waterproof and use something other than wood for the trim.

Can you add a picture that includes the window and tub so commenters can see how far the window extends into the shower area?

sure, here is a pic where you can see how far the window extends into the shower area.