Two curtain rods will work, and now that you describe the window narrow enough to tie back the curtains it should be ok. I do have to mention that you will still get light leakage above the window. Would hanging a blackout shade close to the window, probably outside mount, and then your curtains on a rod work? The shade can be pulled up daily and be out of sight and you can keep your drapes tied back as a style. The shade would probably provide more blackout effect for you.

Oh I hadn't thought of that. That is definitely another good option! So why do you suggest an outside mount instead of inside mount? I guess one thing to mention is that the top of the window sill sits about 2-2.5' from the ceiling, and I would be hanging the curtains high. So when they get tied back during the day, you would see a bit of the wall above the window. Which I'm fine with. I suppose an outside mount could be more visually appealing because I could hang it high enough to hide the wall and give the illusion of taller windows. But, I just wonder if the shade contraption (I don't know much about shades) would protrude from the wall and interfere with the curtain (again, I suppose I could just ensure my curtain rod leaves enough clearance from the wall).

An outside mount shade, roller or cellular, would provide more coverage against light leakage. Neither project very much to interfere with most curtain rods.