At 17 and 18, it will be at least 2 years before we will have any idea whether either will do it here.
It was only last summer the club were publicising their research and how it showed 8/11 players starting in the Champions League 1/4 finals and beyond were playing regular league games at 18.
I think Brahim & Foden are more than capable of being brought through with Mahrez around, but the idea kids should only start playing when they're 20/21/22 is incredibly outdated, and flat out wrong based on City's own research. They need to start making sub appearances in the league and starting all the cup games they can. The fact they've amassed 9 minutes of league time between them is a bit embarrassing to be honest, there's been so many games we could have blooded them in, and Pep would have done so at Barca.