I can't offer any advice or guidance, but I thought I'd reach out as I'm in a similar position. I'm 28 and had blood in my stools and irregular bowel movement for the last 6 weeks. I went in for a Colonoscopy on Monday and they found a 12mm pedunculated polyp (Ip, pit type IIIs) which they removed and tattooed the area. I also had 8 random biopsies and the surgeon said it looked benign. From what I could gather from Google (not the most reliable source I'm afraid but all I have) was that if a polyp is under 20mm, it's much less likely to be cancerous. I no longer have any blood (touch wood) and bowel movements are still pretty all over the place but I think that's expected and they do seem to be settling slightly. During discharge from hospital, I was advised that the next steps for me would probably be having me in on a yearly basis to be monitored so they can catch things early - both a blessing and a curse (Moviprep is the worst!) as they are more likely to come back. This might not be the same for you as they also mentioned a hereditary condition that makes polyps more likely as Colon Cancer at a "young" age runs in my family so they think that it may be in my genes. I hated the colonoscopy, but it is reassuring to know that they will be monitoring it - and I expect given your age you would be monitored closely too (sorry!)

I'm trying to stay positive as everyone is telling me that a doctor wouldn't say it's benign/prevented cancer, unless they were pretty much certain. I know firsthand this doesn't ease your mind (that's why I'm on here at 3 am) but I hope it can offer a smidge of reassurance.