I am not sure whether or not I should keep learning new french lessons right now, because I have had a bit of trouble with old ones. Thoughts? I don't know if it would be helpful to keep going when I am not grasping old concepts.
I've personally stopped advancing in my Spanish tree because I'm not remembering the vocabulary. Currently I'm just strengthening my skills, and making flashcards for words or phrases I can't remember.
Maybe you could try this for a week or two to get caught up before continuing in your lessons? c:
Progress whenever you feel ready. Some like to push through and then revise, others keep the tree gold and progress more slowly. Everyone has a different learning style.
I'm personally very slow with my trees and can't imagine finishing trees as early as some people (French at level 12 is an exception because I have previous knowledge), I like to be sure with a lesson, know the vocabulary and keep my tree completely gold, I only want to look up new words during the new lessons.
So do, what feels right for you.