When can I start to trim the sugar leaves

After harvest! Only yellow dead/dying leaves should ever be removed.

What do you expect to get from that exactly ? Do you have a reason why? If not just keep her growing...

Why trim the sugar leaves. I think you might be mistaken on terminology. Sugar leaves are single blade leaves that form from the buds. It's too early for them, you'll notice them when you start to get some later bud development. Leave them to mature as they get covered with trichomes and depending on the genetics you can even have some fan leaves that get covered in trics. You'll notice them when trichomes start forming. The trics may only appear from the stem to part way up the fan leaf. I leave them on my bud, I don't trim my harvest like a dispensary would. I use the fan leaves along with some other trim to make my cannabutter. You can remove some larger fan leaves especially ones with long stems. Definitely go in and cut off those yellow and damaged leaves.

You can, and should do it now. Go mostly for the ones covering light to lower buds, thats whats most important. As for the lower leaves take out the ones you think necessary for a good bottom airflow but from what i can see, there is plenty of space down there so i would mainly focus on the bottom leaves covering the lower buds. happy grow mate, your plants look lovely!