Congrats! It's always fun to get those first eggs from a new bunch of pullets. Wait 'til you taste them - delicious!
Often pullets will start laying, then slack off for a week or two, then start back up more consistently. Also, the eggs will be smaller starting out and then get bigger.
Black Stars (a sexlink) & RIRs are both excellent egg laying breeds. Once they get in full swing, you can expect 6-7 eggs per week from each gal.
Certainly not less than 5 per week from each bird. I would cull individuals laying less than that after 7 months when the days are at 14 hrs total daylight.