[USA] Immigration procedure for an unmarried child of US Citizen over 25 Y.O.

What's the procedure for me to get the citizenship? Doing a little research I think my father has to file form I130, is this right?

I also read that if we file this in CA, there's an estimated processing time of 4 to 9 years, as opposed to NE where it is 9 months tops. Are we allowed to file this wherever we want?

I was married but got divorced over a year ago, does this still count as unmarried?