Hi Shawna!
You definitely came to the right place! Big Paws Only is an absolute WEALTH of knowledge! There are so many people here with such wide expanses of experience. You will have no doubt learning everything you need to know.
I'm Nicole, and while I don't have a Newfie, I do have a Chewfie! hehe! Cabeza is a 6 year old Newf/Chow mix. He's not as big as a Newf (only 100 pounds) and I rescued him at a year old, so I didn't have the same growth/nutrition issues as a purebred Newf.
That's one thing that you definitely need to consider early...what you'll feed Sadie so that she doesn't develop too much mass too quickly. Also, many Newfs that I know have sensitive tummies, and that is something to consider as well.
As far as training goes, Newfs are super sensitive and don't like it when you're angry or frustrated, so always keep training fun and interesting, using POSITIVE reinforcement. Do you have a local Newf Club? They are a great place to join other Newf mom and dad's, learn about training, go to drafting and water competitions, etc.
I'm just passing along knowledge that I've gotten from Big Paws Only Newf mom and dads They're all awesome, and you'll definitely grow to love and appreciate them (and ALL the BPO Moms and Dads, from Danes to Mastiffs to Berners to Swissys to Dobies to the loveable mixed breeds!)
Welcome!!! Oh, and one of our initiation requirements is MAJOR AMOUNTS OF PICS OF SADIE! HAAHAHAHA!
And those Maine Coons, too!