Depends on what training you choose.
I know schools that will get the job done from no experience to first officer in a Beech 1900 in just 18 months.
you can also go via Universities (get a degree while you get your licenses), and that can take 2 to 4 years.
However, remember that you will be a FO...to be a captain expect some years as First Officer (2-3) and this is just for the aircraft you are currently rated on

When moving up the ladder you'll first be in the right seat - again :)