43 days old, to small?

Those are very small for their age. They should already be starting to flower if they are really autos as they are older than the 3-4 weeks old when autos typically flower. They should stretch a little more but still gonna be pretty small. This is why i dont reccomend autos for beginners. Any mistake or problems will stunt their growth which means you will wind up with tiny plants and low yield. Autos also lovvvvveeee direct light. The more direct light they get the bigger they get. I grow mine under 20 hours of light 4 hours of dark. The only reason i dont do 24 hours of light is because plants benefit from some darkness(its typically when they do a lot of root growth) and it saves me money on my electric bill. It looks like you grow outside so you cant do super long hours of light like indoor growers. That means you need to maximize direct sunlight exposure. So you dont want to plant too early in the season when total light hours are less than 14 hours. Ideally you would plant after total daily light hours reach 14+. That way they get more light and are recieving maximim light hours when they are in the height of flowering. If the location they are in right now doesnt get direct light all day it would be a good idea to move the plant to a better location or move it as the sun moves to keep it in the light.