I will say that you 100% should have the colonoscopy, especially if you have immediate family with colon
cancer. If the colon
cancer is distant, like great uncles, 2nd cousins,etc, your chances of having it are less likely. Keep us updated, but remember there are tons of other issues it could be.
As for the raised alt, I had the same. Mildly elevated AST and ALT, and come to find out it was because I lifted heavy weights 5 days a week.