Was there any info from the breeder on flowering time? 7 weeks feels a touch early, but you’re almost there for sure.
I’d keep using the microscope to check daily (I’m sure you’re on it) or every other day.
You will know instantly when the pistils go milky - you won’t need to think about it, or wonder ‘is that milky? It might be. Let me check again. I think I can see it starting. Hey, is this milky or not milky?’.
I do that all the time.
Oh and check multiple spots.