Just do it, especially if someone in your family had related issues.
My mom did it just because, without any symptoms, and they removed around 9 cancerous polyps (in three different colonoscopies, it ended up being a complex case). Accordimg to the doctor she would have been dead 3-6 months later if they didn't have discovered those unbroken polyps on time.
More and more, we're finding colorectal has very strong genetic correlations.
It's not as strong as Huntington's or BRCA, but akin to carpel-tunnel with repetitive hand motions or melanoma with UV exposure, a diet that's "fine" for most, turns out to be a "killer" for a minority.
