Flowering to early

This is my first time growing an auto flower and it is the fastest finishing one that I have been able to find (60-62 days finish but I am aware it is supposed to be more like 67 most likely). I have been feeding it the same nutrients I previously did for photo periods of the same age but for some reason pistols have started to pop at day 20 and I am aware this can greatly effect the end yield. I have 2 planted a week apart and the younger one hasn’t spouted pistols yet and I am wondering if the younger one is most likely going to be effected in the same way.
it’s a 24/h light schedule but I changed it to that after it being in a 18/24 because it wasn’t showing enough growth each day