First off congrats on making it to module 12, and sticking with it the last 6 months! Roots, fifths, and octaves will take you far in the bass world 
It’s not a race and keeping up a consistent practice schedule like you’ve been doing is the most important thing.
Yes! It’s way too big of jump. I used to try to do this using You Tube too. What I found was I needed to be able make smaller increments. This is true even after you’ve been playing a while. The metronome is your best friend here. Then you can fine-tune it a few bpms at a time until you reach the actual song tempo. I’m doing this now with Zeppelin’s “Good Times, Bad Times”. It’s way to fast for me at 100%, but too easy at 75%. I spend about 10 minutes a day working my way up. Am at about 90%. I’ll get there eventually and you will too! Once you get to full speed, you probably won’t even have to think about it anymore, it will become autopilot. But its a grind for sure.
Keep up the great work