You won't regret it
Trust me, I know. Family pictures are kind of the worst. I've said it myself with my own family. But I promise you, if you just do it, you won't regret it. Don't wait to lose the 10 pounds, don't wait until you have found the perfect matching outfits, don't wait until you have found a location that no one has ever thought of, really... just do it. Photographs of your family will be something you will treasure forever. In 10 years, you won't look back and say, "I wish I wore a different outfit" Instead you will just be grateful for the memories a simple photograph can bring back to life.