Do you think Bitcoin will become the first world currency for buy and sell ?

I'm not exactly sure what you mean by this, but the USD has already become a de-facto global currency because almost everyone accepts it, you'd be hard-pressed to find someone who did not want to have USD as a seller, but that's just because it's a lot easier to tax people and not have anyone revolt against you for controlling your nation and having the standard geographical distances between the two locations. Hell, they even said this in Skyrim, if you've ever played that.
Bitcoin might be the second, but it likely won't be accepted for a long, long time to come.