I agree with hoeklijn, you need to air and flip the cheese once or twice a day depending on how damp the rind is.
I pierce my stilton-esque blues around 10 days, my rinds usually have enough blue on them at that time.
if the piercing get's plugged up with the flora I re-pierce, that usually happens about 3 weeks into the ageing process.
air and flip at least once a day until you think there is enough blue veining on the inside or you're day of cutting.
one thing about blues, they will get moldy, they will get scary, you're gonna worry and more than likely you're gonna freak out.
It's all good