BlackBerry

next time use feminized photoperiods, you have more control since you can decide how long to keep them vegetatively with 18 hours of light and you can send them into flowering simply by moving the timer to 12/12

I think this is pretty common. Flowering at 4 weeks is pretty normal. This is why I’ve yet to grow an auto. Seeing so many others grow them with such little control puts me off. I doubt you’re doing anything wrong, it’s just being an auto.

38cm isn't very tall really but it should still get bigger. It's pretty average for autos to begin flowering in the 3-4 week range. Then the stretch hits and if everything is in check it doubles or even triples in size over the next few weeks. Light+warmth+proper feeding=success.