The future is technology. You're holding them back, socially and technology skills wise, if you wait until they're 13 to give them a cell phone.
I was fixing computers and was generally the house technology expert well before I was 13. To get to that point required unrestricted access to tech and the internet. If I was locked down until 13, I would not be as successful as I am today in tech, if I was in tech at all.