I know quite a few ex-Cpts (joined as fast-track F/O) still being SENIOR F/O's and no end in sight after more than 8 years and more (they now have an additional problem being the age). Your 'upgrade' is not an objective and logical path. Being expressed in time or anything else(part A) . It is an ABSOLUTE subjective occurrence pending approval from certain people. If you are the lucky lad it can happen in 2 years or else it can not be expressed in time. I hope this answers your question.