Good for you for making the decision to live a healthier life style! SP is a great site! You'll find lots of resources here to help you... You might want to design your SP and make it public so that people can visit you and get to know you. Personally, I've found that my friends are my biggest motivation. Posting on the message boards of your teams is a good way to meet people and make friends.
Probably the two best things you can do to help you reach your goals are to track all of your food, and to commit to at least 20 minutes of exercise a day.
I wish you success on your journey! Blessings and