The Biggest Loser League

Currently I weigh 225lbs., my goal is 120lbs.  I want to lose atleast 100lbs. to feel, be and look healthier.  Though I am married, I am in this alone.  I will admit that this scares me because I have never done anything alone.  My partner feels that his being overweight is not a problem, however, as a female my self esteem has hit an all time low and it is time for a change.  The saddest event with my weight was having to watch my family play softball at my nieces birthday party and I could not join in because the weight weighed me down.  I need to do this so that I can have a healthy long, active life with my family.  I don't want to be the fat friend anymore, I want to be the girl in the room that everyone wants to meet and the girl that my husband fell in love with.  I started walking yesterday and today I was extremely sore, but I still managed to walk.  Is there anything I can do for the soreness?  Please help.