Looks like you have some issues. For 40 days your plant is extremely small.
You should not remove any leaves at this point, it will only stunt growth.
Also, the 55 degrees at night is a bit too cold and will affect the growth as well.
You also have nute issues, very likely that is because your PH is off.

When I started I had similar issues, and then I got the PH right and in 30 days my plant was over 1 foot tall.

Best of luck!