I think you're doing a fantastic thing! I can, of course, understand why you are uncomfortable with it. I also held myself back from joining in on many activities in high school (and college) because I felt uncomfortable with my weight. I'm just now trying to break out of that habit, as it's severely restricting my ability to go out and be who I want to be. Don't wait until you are at your goal weight to live life. Be nervous about it, that's normal - but be proud and confident too! You never know who you may inspire.