Hello HC Members

,
My 03 Accord Cpe maintenance light has come on, and I do not know what to replace yet. My car has 48,900 miles and bought it 2 months ago with 46k. However I do not have any previous service records for the car. I recently got an oil change, but I was looking in the Manual and it says the Tranny fluid needs to be replaced every 15k miles. I have an idea that the tranny is the problem because when I driving from 30-50 it holds its gears. For example I will be coasting and it will be hold at 2k RPM's for like 5 seconds before finally shifting. And no other part needs to be replaced, around this mileage time. Is it possible I need a complete service at 50k miles?
Is it possible the light is on for no reason?
Thanks a lot guys for your help, peace.