I flight instructed for 2 years, then went to the regionals. Was an FO for 1 year then upgraded to a jet. Was a Capt for 5 years with 2,500 jet PIC and still cant get to a major any time soon and this was durring amazing growth at the regionals. Growth that will never happen again, so I think your talking around 10yrs to get to a major. However luck has a lot to do with it.