Social Media Access

At what age do you believe a child should be given a phone/access to social media?

My kids got a phone when they were around 11 I think, but just a flip phone to call with. With 12 in high school they had to have a mobile phone with apps for school homework etc so then they got em. We gave the kids a Facebook account when they were around 9. Son got all these aunts as friends and his dad would put a pic on it from a painting he made and an aunt he didn't even know said: oh how nice! You have done that very well! Son: Mom can you tell her I have no time to respond. I have to play outside. LOL. Facebook is for old people. Removed it again but it was handy that they had an account so we could video call with Messenger.