Tall as a tree

After explaining to alice that when some kids are old enough their
parents let them ride their bikes home on their own...

"mummy how grown up do I need to be to ride my bike home from school
on my own?"

Me -" oh a fair amount more! Your still little"

A -" how about when I'm as tall as that tree! Mum! When I'm as tall as
that tree would I still be able ride on your shoulders?"
(the tree in question was a HUGE oak!)

Me - "alice, when your as tall as that tree you will be able to give
me rides on your shoulders!"

A -"that's a brilliant idea mum!"