I am not sure what was said to you before, as I don't post on here very often. I know that many of us are very passionate about the subject, and may come off rather strongly at times....but I am glad that you weren't scared away
I am also a non-confrontational person by nature. I am definitely working on becoming more assertive. Having my son has definitely helped me with that. I want no harm to ever come to him, and my job is to protect him. I have become much more assertive when it comes to anything to do with my son.
I find just saying no in a firm tone with a look that says that it isn't up for discussion is all it takes. Saying no to circ is relatively easy, as opposed to say declining vaccinations or vitamin supplements(I don't think bf'ed babies need them personally)....docs usually give me more hassle about those issues. However, I've always been able to say no to them....I nod and smile a lot....and let it go in one ear and out the other!
When I had my son, the nurse asked me the day after he was born if I wanted it done....I was in the bathroom at the time, and she just knocked on the door. I yelled NO, and never heard another thing about it....LOL.
The more informed you are on things, the easier it will be. Armed with research, and the sight of your precious newborn son, I think you'll have less trouble saying no than you might think.
Hugs and congrats on your little guy!