Austin’s Heel Turn At W.M. 17?

Back when the WWF/E used to actually plan out Wrestle-Mania fairly well in advance, was Steve Austin's heel turn against the Rock at W.M. 17 always the endgame several months out, or was it a fairly recent thing they just went with?  I can't explain why, but I always felt that it was a relatively last minute decision.  Any ideas?  
It was not last minute at all and there was a lot of convincing and hand-wringing on both sides leading up to it.