I love your plan Stephanie!
Being realistic is the first step forward in this journey. The nutrition and fitness trackers are so helpful. I think making your health a priority is a wonderful thing. I only wish I had done so at your young age.
Poke around the site - try the exercise videos and demos, read the articles, try a few spark recipes, join a team or two of common interests/goals and read personal blogs. You can begin with one of mine: www.sparkpeople.com/mypage_public_journal_
Whatever you do - don't give up. The destination is not optional, the journey begins!