Shouldn't my plants be taller??

A lot of people mistake height for progress. Height is simply the plant trying to get as close to the sun as possible. What matters is the amount of leaves it have on the stem, as they're the ones actually catching the light it uses as energy to eat. - As long as there's enough space between nodes for the plant to develop buds, height isn't a big concern. - I'd go so far as to say, that it wouldn't hurt if you lowered your light more than it looks on one of your pictures, maybe to half its current distance from the plants. Your plant looks pretty normal sized for an automatic from a first time grower, after 3 weeks. They'll get increasingly taller from now on anyway, as they prepare for flowers. You'll probably see it double in height over the next week and a half, and it'll probably get even taller after that,until it starts giving all its attention to the buds and growing crystals in its attempt at catching pollen.

Hey, Nice grow! Your plants are right where they should be, so far they are looking healthy and happy! Just wait another 3 weeks and that thing will probably be several inches taller with many more branches shooting out. Just make sure you’re not overwatering and she’ll explode!

Hey Pal, As long as your Damsel looks healthy, they do not look bad, maybe a bit dark but that could be the quality of the photos. It's also a bit strain dependend.. some are more bushy and small with short internodial distance others grow with bigger distances. You can move your light away from her, she surely will stretch for the light. If you're satisfied with the height, set your lights more closer. Good luck and happy trails for the rest of the way 🤞 Servus OimRausch

As long as your plants aren't getting burned or risk over heating and provide adequate canopy coverage i don't think the distance matters, but you get tighter inter-nodal spacing with a closer light, yours look pretty tight, idk what to expect of a plant that age im a newbie but if you're concerned the light is to close you might just have really tight internodal spacing which is great plant stretches less, more compact can hold more weight about 1 inch - 1.5 inches. yeah but as for the rate of growth im not sure, if those were my plants id be happy though :D gl idk if its just the lighting but Holly looks better