You have to find your own pace, of course. But a tip I give due to personal experience: I really recommend trying to learn full songs. Even if you just play 30% of the songs because other parts are still too hard it really helps prepare you to play with others, because you don’t have the tab/sheet music right in front of your eyes and have to remember the form of the song yourself and have to make sure you’re in time without Josh counting along…
I mention this, because I rushed through the course, barely experimenting and practicing full songs - when I got into a band I noticed that these are exactly the things I’m missing. It got better quickly, but it probably would have been easier to do it right away.
Then again if you already been playing for 18 months you might have already done that.
I am just saying that the lessons are easier than playing a full song and I recommend working full songs into your practice - even if you can’t play the whole song because some parts are too difficult. Even just playing the parts you can will help in my opinion.
Also worth mentioning for additional practice and more info on techniques is the youtube bassbuzz guide that lists all bassbuzz videos and shows to which modules/lessons the video corresponds: