Pre-flower?

Hey, these are 3-4 weeks from sprout.
Tent is 60x60x180cm and already crowded horizontally. Should i flip them this weekend or it will cause them shock?
Also, can you tell the sex yet?

If your running out of space you can flip, they will at least double in size after. I'm in Rdwc so I can see my roots vs container size as well as how much room there is in my tent which is helping me make my own decision. If they have room to grow up mostly but out a bit and room for more roots continue to veg and you will yield more, your end goal and available space are the determining factors along with light, temp, ph, nutes ect.

Didn't answer one of your ?s. What you're looking at is new growth and won't know sex till you flip