Although I do think SS will take place a LONG time before OoT, I personally don't think it'll be quite that long. In OoT the Master Sword is a legendary blade known by mostly everyone in Hyrule and still has it's own Temple built for it. For this reason, I don't think its actual creation (which...
Well I don't think it would really matter how much earlier SS takes place. The Great Deku Tree and all the Kokiri are most likely REALLY old.... at least, they can be simply because they all live forever. Unless there is specific evidence saying how old they are in OoT (which I'm pretty sure...