Actually, you are really supposed to be 13 before you have an account on any social media, such as Twitter, and Facebook, and Instagram, so really, It is geared for people 13+. Even email! But I believe it is every parents choice to make. If they let their child have a Facebook account when they are 7, so be it. That is their choice, even though it might not be a good one.
Trust me, I want a Facebook account, but I am only 12. But I have an email address, and I got it when I was 10. So just ask your parents.