Is it easier to make friends when you are an adult or a child? Why?

I think making friends in childhood is easier than in adult time. Usually children choose friends on the playground, at school or kindergarten. And children are kinder and more trustful than adults. Children usually share their toys or other things even with new friends they don't know well. Adults sometimes try to check their new acquaintances in some time or at once. Adults have formed character and opinion. So I suppose they make friends very carefully, but not always. It depends on people's social position, I guess. Some people make friends only for benefits, some try to have friends really for support and love. Making friends is rather philosophical question.