when will I take over the world?

There could be many variables, your age for one, but from the example
of Alexander the Great, we should be careful about suggesting that a
young person could not take over the world.
Then there is the question of your power base.  Alex had one, if you
still need to develop one, that could take a while.  Since I reckon
that if you already had one, you wouldn't be here asking this, I
expect that it will be a while before we all become your subjects,
say, 20  - no -  23 years and two months.  That would be about
December 2028  - let's say by New Year's Day 2029.  Okay?
But it won't happen if you just wait.

If you have to ask that, you will never take over the world. Any true
world conquerer knows his destiny, knows how to achieve hist destiny
and actively works towards it. Something else to consider is that
those who take over the world are never satisfied. Alexander would not
have been satisifed had he lived to govern the entire world. Instead,
he would have been looking for something else to make him greater
still. Hence the story of when he heard the philosopher speaking of
all the different stars and how each star might have planets like
earth ad infinitum. Alexander wept because, "All those worlds in the
Universe and I have yet to conquere but one"

--SENATUS

You will take over the world shortly after I finish with it.