FC Porto

[Mingos]

Ainda não, para ser considerado formado no clube tem de estar 3 anos entre os 18 e os 21. Ele começou a época com 17 ainda.

Acho que é entre os 15 e os 21.

EDIT:
A “club-trained player” is a player who, between the age of 15 (or the start of
the season during which he turns 15) and 21 (or the end of the season during
which he turns 21), and irrespective of his nationality and age, has been
registered with his current club for a period, continuous or not, of three entire
seasons (i.e. a period starting with the first official match of the relevant
national championship and ending with the last official match of that relevant
national championship) or of 36 months.