Welcome! Getting started is always the hardest part. I think Spark gives you the tools to be successful; it's just a matter of making them work for you.
Definitely join a team challenge! There are a LOT of them, so you can always find something helpful to you. Like REBCCA said, the community boards are also a great place! Feel free to friend me and check in with me.
It's hard to get excited about your weight loss when other people are doing it faster -- but it's not a race! Not everybody is going to lose 100 pounds in a year. Focus on yourself and your own goals -- you WILL get there!