Is there any reason the gym order is the way it is? I'm mainly speaking Sabrina before Koga, as I haven't seen the other regions yet, but in the games Koga is supposed to be fought before Sabrina. (I'm aware they open up at the same time though)

Every time I played 1st gen games, I would battle Koga first. I was always under the impression that Koga was before Sabrina and put it in the game this way as an easter egg.