Welcome Madd,
I’m also new to Indoor and just had a successful harvest with two other plants in flowering…
Looking at the photo you posted, I have a suggestion: Change your pots! It turns out that your plants get most of their air through roots, so you must ideally not use a fully sealed pot. In a sealed pot, roots will grow all around your compound looking for air and this will greatly limit the nutrient intake.
To solve this, you can find plastic pots with holes on the whole periphery that keep water inside but let air in, or you can also find grow bags that have the same property. This will ensure a regular and dense root network and proper air (Oxygen) intake for your plants.
Also one thing that is really important is the PH when you water: check and correct each and every time, feed slowly in small steps and better not enough than too much.
With this and all the good advices already posted by @Ratch33 , your babies will grow to their full potential 
Enjoy!