Why doesn't it mean "About a hundred years"?
Why not 'om en hundra år'?
It's wrong. Swedish just doesn't work that way.
Why om and not i?
Prepositions are used differently in different languages. That's just the way it is. "I hundra år" means "For a hundred years".
Wasn't om supposed to be about or if, is the word for about like in about a hundred years different?
...när vi är tillbaks på noll?
When someone asks you to go out with she/him too much.