Changing my oil

I have a 98 Lumina 3.1, and have put about 2.5k miles on it already. Since I have no idea of the cars history I was going to do an oil change. Can anyone tell me if the oil change light is a good indicator of condition of the oil and filter? My light is not on yet, but I really dont see the need to wait for it to tell me. Also does the oil change light turn on after a certian amount of miles? e.g. if I did the oil change now, would the light come on anyway after say 3k and then I would have to reset it myself? or will the computer detect that I have performed an oil change.

Thanks

I had a 97 lumina with an oil change light
the computer monitors driving conditions to gauge the life of the oil.
my lite would come on after 5700 mi.
sounds like a ton of miles to me so I would change at 3000, lite still comes on, just have to reset it

Hey, Thanks for the info.