Learned a lot with my last grow, doing much better this time. They’re already much further along than the last ones at this stage. No nutes will be given until the first rounded leaves turn yellow.
Leafs are fragile. Excess air movement and friction, or any abrasion of the plant to even itself, can result in that. Nothing to sweat, you’re all good. Healthy looking seedling. You’ll be fine, keep up whatever you’re doing.
Cheers