Can i get a rectal cancer at age 15?

Very uncommon: The earliest I have seen colon cancer is age 17. Unfortunately it occurs but extremely rare, mean extremely rare. Family history plays a big role. Things that may help are eating a healthy diet. Stay away from fatty foods. Hope this helps.

Rarely: Unless you have ulcerative colitis. Other tumors and inflammatory conditions of the anorectum are more common at your age, so if you have any symptoms of bleeding, pain, urge to defecate, diarrhea, constipation, or bladder symptoms, see your doctor for a simple rectal examination.