To create a good security question it needs to be memorable, but it also needs to be something that other would not be able to know.
A bad security question would be "my favorite color". This is because your friends may know the answer to this, or this may be on your social media.
A good security question would be "How old were you when you got your first pet". This is because this information would be harder to find, but still memorable for you.
Because these are used as example, they will not be able to be used on this website.