Can I create my own CRM company reselling our version of CivicCRM?
I think the answer is probably no, but it depends on what the question was.
My reading of section 5 and 6 in the licence as linked by @demerit https://www.gnu.org/licenses/agpl-3.0.en.html
means that you can't &quot;license&quot; the code itself, even if you modify it, except by using the Affero license, i.e. you can't charge money for it.
What you can do and what others do is to earn money by providing additional value over and above the code base in some way, typically some version of hosting and/or support.
Conclusion: earning money by selling/renting the code is not allowed, even if you modify it.