Advice

Personally, I think a better use of your time would be to start using resources like Mozilla Developers Network or Google the information that you need. It's kind of a myth that experienced programmers just intuitively know how to do stuff right off the top of their head. Sure certain tasks get easier with practice, but I constantly have developer docs or other resources open when I'm working on projects.

If you have a grasp on the basics and can generally understand the documentation it would serve you well to get used to using it. Obviously, if you are still struggling with some concepts then go back and watch some videos and complete some code challenges.

People have different learning strategies. Only you can determine if you need to start over after your gap. But perhaps a faster catch-up method might work for you. You could skip past the videos and take the challenges and quizzes again, and if they reveal anything you've forgotten just review those videos.

There are a bunch of 'practice' workshops in the library that kind of just go over the same material again. These might be good refreshers. (Some of these will be more advanced than you are though)