If you want your future CAS to be (probably) a 3* by the time he's about 50 (sorry! or she!)
That's a dated perspective on age vs rank. Service to 60 changed things immediately, most notably in the wg cdr / gp capt bracket where ambitious new promotees are told to expect 6-7 years in rank (there is a 4-year minimum seniority requirement and still the 'command and staff' hoops to jump through. The best will manage it in 5 years but that's still much slower than your example). Then 1* is no longer the holding rank that it was in the old days; there's now expectation of 3ish years as a Force Commander or ACOS in posts which have assumed more responsibility since the Levene reforms. It's only after that that things can really speed up. The new CAS was a 3* for less than a year...
My sense is that 1* by 47-48ish is today's marker of potential. You're still right that the current crop of junior officers are going to struggle :-(