You can buy stickers to go on windows that are visible to birds but not as visible to humans to prevent this. Sadly many birds that hit windows aren’t as luck as OP’s bird.
The stickers are much cheaper online than they are from a specialty bird store. Curtains or blinds are also effective, of course.
It had hit the window, but flew away,
Is it okay?
Yes, OP said it flew away :)
Yay!
You can buy stickers to go on windows that are visible to birds but not as visible to humans to prevent this. Sadly many birds that hit windows aren’t as luck as OP’s bird.
The stickers are much cheaper online than they are from a specialty bird store. Curtains or blinds are also effective, of course.
+1 The stickers are not fool (bird?) proof, but they do help a lot.