It's extraordinarily rare for people under 30 to have colon/colorectal cancer. I went to the doctor a handful of years ago for some digestive system issues and my doc told me the #1 reason by far for blood in your stool in younger people is hemorrhoids.

You absolutely need to get checked out, but I personally have way, WAY too much experience fearing the worst about things only to find out in the end it was some minor shit that was pretty easily resolved. Stressing over what might be, only makes you miserable for no reason at all. Get answers first before thinking the absolute worst.