Basically you are one that needs frequent colonoscopy's. I am not sure on how long it takes for neoplasms to grow, if you have health insurance from your work or what not you may be able to request them yearly. Being worried is human, but at least you were able to find out about the polyps while they were easily extracted. You might be able to talk to your PCP too see what he or she thinks.
I was as well found with cancerous colon polyps. They recommend at least 3-5 year check up on sometimes the size of the polyp. They don't want to check on colon polyps every year unless needed because when someone gets an endoscopy or colonoscopy they fill your stomach with air which give you a hernia until you release the air.