Just an FYI, CF does not fatigue in the manner that aluminum does. Aluminum and many other metals can take a certain number of cycles before cracks start. Carbon fibers remain intact over an infinite number of design load cycles, yet CF yields suddenly when overloaded.
The CF spars on Extra 300 aerobatic aircraft are subjected to 10 or even 11G of loading on a regular basis. Because it's well within it's design load limits, no fatigue damage is being done and decades of use does not weaken it. Same with the Boeing 787, years of turbulence, heavy fuel loads and passengers does not weaken the composite structure.
There are other problems with certain CF bike frames though. The bottom bracket and other metal components are often installed with an epoxy that is different (less robust) from the one used in the composite. On some frames, those epoxies can degrade over time and on some models, corrosion at the CF/metal interface can become a problem. It would be a good idea to research your frame and see if it was prone to problems. If not, then ride it with confidence.
It's good to keep in mind that on composite structures, paint cracks do not indicate material cracks. Composites can flex and paint, especially old paint, often does not.