Eh, I don't know. I've talked about this with fans at other places, and I just can't "agree" with how it's set up. Others have told me its official and that it's not possible to disagree with, but it makes about as much sense to me as it would if JK Rowling said that it's official that Harry Potter was actually a magical talking lamp rather than a human the whole time.
It's also clear to me that the creators decided to just put together a timeline in maybe 15 seconds, without any effort put into thinking about what would make the most sense, or having to come up with absolutely ridiculous excuses as to why it is this particular way. That's pretty insulting, especially after going through every single little detail in each one of the games and thinking extensively about them. The debate of a split vs. a single timeline was legitimate by itself, but a hypothetical "what if Link failed" just seems extremely lazy.
I just can not take whatever the creators say with more than a grain of salt anymore. I feel that each subsequent game will speak for itself.