Auto grow , started flower?

I usually switch to bloom nutes 2 -3 weeks after these first signs, for me it usually works out being around the end of week six, you can shock the plant if you give them too early and you would call this phase "pre-flower" rather than full bloom. Your plants looks fine though, if you rush on nutes you might cause more problems than if you wait a bit longer. Good luck.

Pistils = fem You're good!

Give it another 2-3 weeks or until there are small tufts of pistils/budlets forming before switching to bloom nutrients, a few pistils does not mean a plant is actually flowering, just that it it is going to do so, soon. Cannabis still needs adequate nitrogen during early flower and switching to bloom nutrients too early is a common mistake I see all too often. As ezzjaybruh said, continuing with grow nutrients for the first 2 weeks or so, then a week or so with half grow and half bloom, before then finally switching to straight bloom nutrients is exactly what I have been doing for 30 odd years and it works well.