We know that characters start making Aging rolls when they reach the age of 35. Characters with the Strong Faerie Blood virtue start making their Aging rolls at age 50.
We also know about laboratory routines that:
Question is : how does this rule apply to characters with the Strong Faerie Blood virtue ?
Yup. That is how I would read it as well. Basically a character with fae blood counts as being "young" from 0 to 49 years old. 50 onwards he gets old like everybody else. The only difference is the threshold where this happens (35 or 50, quite a difference indeed) and the extra bonus he gets from his blood, but apart from that, same progression
Adding to that, we also use aging rolls if the total is bonus, except then a roll cant result in a bad effect, so you basically roll to see if your apparent age changes.
If for example you have SFB, the covenant has another -3 bonus to aging rolls from location and you manage an outstanding -3 bonus from living conditions, people grow up and then apparent age then doesn´t change much until the age modifier grows large enough(because you start out with a -9 modifier to aging roll).