If the gamecube came out 2001 how did the legend of zelda ocarina of time come out 1998?

It was out on the N64 first. Not the GC first. OOT with that dual disc one I know cause I have it came out for the GC to give players the abilityy to play old games that are just updated for the GC. It was a 'Bonus Disc' for the WW when it came out. OOT was a nice addition to the GC sadly they didnt update much of any other game I am glad they did for GC that was a good one along with the, Master version on the same disc.... I think it was master version.. what ever the upgraded version of it was it was in blue. My Fiance has the System now with the game and she is kinda far away form me right now I jsut dont remember the name. But that is the reason why. It was for the N64 firs.