I'll let Silkie breeders chime in for the final word, but my experience is you never decide this young as a lot can happen before maturity. Roosters especially take longer to develop. I'd wait until at least 6 to 8 months, and many roosters not until a year, before deciding if this is a top breeder for my plans.
Agree with @Lady of McCamley cockerels take loger especially silkies. Your silkie dosent have black skin so he will be good enough for pet quality rather than show or good quality. He also has the wrong eye color, and no blue earlobes. What makes you say he is a he? 2.5 month is way to young to tell gender on silkies.