No that's accurate to how it should be. (If anything I suspect the station could appear quicker). I think you may be underestimating the magnitude of speed and deceleration when you drop out of supercruise. Even though you slowed right down in supercruise to enable a safe drop, you merely slowed to
slower than the speed of light, not actually
slow; you are still travelling mindbogglingly catastrophically fast when you drop.
In supercruise, even when you are "completely stopped" - travelling as close to zero as it is possible to go - you are still travelling approximately a hundred times the top boost speed your ship can reach. And typically at a station you are coming in a
lot hotter than that. The station comes up so fast so quickly because you're moving towards it at seriously that speed, and the ship slows down to regular speeds nearly instantaneously, all handled by flight computers.
Planets are much bigger and much further away than stations, so they take longer to fill your screen at similar speed. Same way it can take hours of cycling towards a mountain before it fills your vision, but cycling the same speed eye-first into a falling leaf, it will BLAT into your face and fill your vision nearly instantly
You raise an interesting question though - does your speed in supercruise when you drop affect the speed at which you see the station approaching at the end of the drop? I suspect the answer is "no", but now I'm going to have to check