Yes, Id been well into the intermediate lessons, and Blues, when I did BLIM.
To get the absolute most out of the BLIM course, I’d suggest a solid basic competency in at least the minor pentatonic, and the 12 Bar form. Know them. Hear them.
As the name implies, its an intensive course, and the more basics you know, the greater you can dive deeper into the more advanced concepts built upon these basics.
And you’re right, its not going anywhere; and will likely improve more over time.
Looking forward to hearing some Blues from you. 
All the best,
Cheers, Shane