Your consultant would not have been able to tell from the colposcopy whether or not the abnormal cells in your cervix are cancerous. This is a very specific process of diagnosis that is done by pathologists in a lab, using very sophisticated and detailed techniques, not by consultants with big magnifying glasses! All the consultant would have been able to see is where the cells were abnormal. Because CIN 3 can cover up to 2/3 of the area, she might have been able to see, for example, that you probably don't have CIN 1 because the area of abnormality is not microscopic. She would not have been able to tell anything more than that though.
It can take up to three weeks to get the results of a biopsy. This is partly down to the amount of work they have in the lab at the time and partly due to the types of tests they have to do in the lab with the sample. Even if they had nothing else to do, they still wouldn't be able to assess yours in, for example, one day, because there are certain tests that have to be done that take several days to get the results from. Then based on the results of those tests, they do other tests. etc etc... It takes time, unfortunately.
I know the waiting is horrible, so I really feel for you. It's really important to keep in mind though that CIN is NOT cancer and there is no reason to think it would be - in the vast majority of cases, it isn't cancer.
Take care of yourself and let us know how you get on.