The time from entry to upgrade is always hard to predict exactly, and I personally believe that 15 years might be slightly exaggerated - in the end it all depends on future development of the company, plus their willingness to hire at least the amount of people that they can provide training for themselves.
As a matter of fact, I haven't seen anybody hired 2001 or later who managed faster than 10 years. On the other hand, a big number of captains who joined CV from 1997-2001 is now in their 50ies and will retire within the next 10 years. Flight Ops Crisis Management yet has to come up with a concept how to ramp up training volume in order to replace those.
But then there is another problem, that they almost completely removed the horizontal move from FO to Cpt pay scale (for new hires from 2016 on). Which means, that after an upgrade after 10 years, you will approximately earn 1000€ net more, that's it.
If that is worth the extra responsibility or offers an interesting perspective, I leave up to you.