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I would say the likeliness of being broody won't change. Even though some breeds of chickens are known to be more prone to broodiness there are differences even between related birds... I don't know why the hormones affect some more than others, but they do. And even if they are broody and willing to set it doesn't mean they will be a good mother... some hens just don't have the patience for it.
As an example... I have 5 Silver Pencil Rock hens who were broody hatched late last spring, from the same breeder, out of the same breeder pen so the genetics are very close (most are probably half sisters if not full sisters)... 2 went broody by the time they were 8.5 months old, a third at 9 months and a fourth one is thinking about it but isn't committing... the 5th is just cruising along without a broody thought in her pretty head.
Silkies in general are about as broody prone as any breed can be, so you have a good chance of ending up with a broody... time will tell if she will be a dedicated one or not... hopefully she will.