Right away!
1. Building a CIM uncovers gaps in your understanding & DD.
2. Socializing a CIM pressure tests the thesis and uncovers key weaknesses.
Ps. Rather than letting AI have a first pass, my recommendation is that you draft the CIM manually first; write out the whole argument (bullet points), list a complete SWOT for the market & target company, and then ask AI to supplement this analysis/sketch.