Welcome, Jennifer!
You will find that this site is a great source of support and advice...take some time to read the stickies, if you haven't already.
Since you want to lose 100 pounds, have you considered breaking that down into smaller, mini-goals? That way it does not seem so overwhelming...that's what has worked for me. I rewarded myself for every 10 pounds I lost...but not with food! LOL!
Good luck!