Watering is my first guess, but it looks like you're watering properly based on the absorption pattern I see in your photos.
My next guess is that you have given her nutes already. Her leaves are rather dark for a baby. She doesnt need nutes until the round leaves start turning yellow. If it's a premixed composition, all you can do is wait it out.
I also noticed you use rainwater. Sometimes this can be way too acidic so you should check the pH.
No rash decisions yet, it's just a little drooping, see how she develops.