When should I get my first colonoscopy/sigmoidoscopy

I am a 52yo female, and I understand the importance of getting a baseline colonoscopy.  I had the fecal occult blood test in August and it came back negative for blood in the stool.  I asked my doctor to refer me to the gastroenterolist so I can schedule my first sigmoidoscopy.  He refused saying that because there's no blood in my stool, I just need to take the blood test again in August.  I believe that you do not have to have blood in the stool to have polyps, and that a baseline test should be given.  
  What is your opinion?

[jdwithhcv]

You should have a baseline colonoscopy at age 50, earlier if you have family history of colorectal cancer.   Your doctor is misinformed - demand that test right away.  Colonoscopy saves lives!  Based on my family history I should have had my baseline colonoscopy by age 40 or earlier.  I did not have the test til age 46, by which time I had Stage IIIc cancer.  Get the test, it will give you peace of mind and you may save yourself a lot of grief and pain.  Good luck.  Please post again and let us know how it goes.

jd