I work with closely-owned middle-market businesses on a daily basis. It's unlikely that a member of the adcom would have a background like mine, but based on my experience, second and third-generation family members generally tend to go out and test the waters immediately after undergrad. If their plans or venture fails, they come back to the family business and stick around for the majority of their careers. I've never seen an instance where someone stuck around the family business for a while and then split off to start their own company.
So really, my question is more out of curiosity and may or may not be something you might consider fleshing out in your goals essays - what will you learn in a post-MBA role at your family business that will help you start your own company that you can't learn without an MBA? If you're working in your family business now, I'd think you won't get much by returning there after an MBA (unless you just wanna drop some newly acquired MBA knowledge on the family business out of the kindness of your heart), so why not start your own company immediately post-MBA?
I don't mean to grill you, they're just questions to consider...