No falsehood. If a new friend has to guess your true character, a childhood friend already knows everything. You'll be comfortable talking to them.
You may be an introvert type. When meeting new people, you will have trouble starting a conversation with them. But not so with old friends. You will feel comfortable and engrossed in chatting with them.
Your friendship is also known to your family and your friends' family. As a child, you must have been invited to eat at your best friend's house, right?
