Hi I am new to this site, But I am going to do WW at home. I have the books, and I officially started Yesterday!

And I have to admit, I am not liking the no soda thing

I have a lot of weight to lose. A lot of Pregnancy weight, as well as added.
I am currently needing to lose 85lbs.
Should I exercise? Or will the WW plan work for me?
Any suggestions, that might make this whole WW-at home thing alot easier for me?
Also...I have instructions for Both Flex & Core plan, which one is better for the amount of weight I need to use?