Seedling looks fine. Try, in the future, not to take pics under the blurple lighting. Mine as well be in black and white, no real color distinction. Seedling should be fine though. I wouldn't use rockwhool unless you're doing hydroponics. If you're doing hydro, rockwhool is awesome in my own experience.
*EDIT* Also, just because someone is rude to you doesn't mean you get a raincheck on calling the people trying to give you good advice douchebags. If that's your style, then go to some weak ass site where mods delete any "negative" comments that might hurt some strangers wittle feewings. Because we do not sugar coat our advice here.