In the short term, it's probably okay because the baby can't get tangled in the floor length curtains or pull up on the safety bars. That's assuming there's no draft and the curtains are black-out types so the rising sun in the spring doesn't have both kids up at 4:30 AM!
Long-term, be sure you don't ever need to open that window, that the 5 year old won't decide that the crib gives him a nice boost so he can grab onto the safety bars and play "Spiderman" to climb to the ceiling, and that the curtains don't give an 8-month old something to grab onto when learning to pull himself up to a standing position. Some kids do fine when you rearrange the room down the road, and others freak out with a change.
Be sure you are bolting bookshelves and tall dressers to the wall so that kids who climb them (including using the drawers as "steps") don't pull things down on their heads - which make make later rearranging more problematic unless you don't mind unbolting and then sparkling and repainting.