How old were your kids when you stopped being COOL?

Turns out it was at the age of 7 for Jennifer Garner's child, Samuel when he figured out his mum was no longer cool.
She put together, I think, a pretty impressive costume for her son's 'How to Train a Dragon' birthday party. Jennifer went all out dressed up as Astrid, complete with face paint, a fur trimmed collar, leather gear and big boots.
He wasn't impressed.
At what age were your kids not feeling your 'coolness'?

