I have done mine at 50, you are half asleep, does not hurt, you do not remember anything. Fasting day before is the worst part.

All in all, nothing to worry about, just do it.

While earlier detection has been beneficial, there's such a thing as too much. Really, there's balance to be struck. For instance the detection procedures themselves (even things like non-invasive imaging) aren't risk free themselves, false positives can set off a chain of events that carry their own harm, and even it's not at all uncommon to develop cancers you "die with" instead of "die from" but once they're detected you have to assume the worst - and treatment itself causes its own form of harm.

Getting one annually is not recommended for most patients. After my bowel resection, I had annual colonoscopies for five years, then every three years, now every five (the normal recommendation for my age cohort).

Colonoscopies are no big deal from my perspective, but they do have some risk; bowel perforation being the primary one. The prep stuff is the worst aspect for most patients; I used to love lemon lime Gatorade before I used it once as a way of drinking the liquid laxative...