Well, how old are you? Are you good at swimming? How long can you hold your breath? And do you believe hard enough?
If you have the upper body of a human and the lower body of a fish, then I would probably say "yes".
Yep you are
If you have gills, there is a good chance you are.
Yes I think sow
Samyd007! There is your stupid rude mermaids aren't real riff raff again! And you probably aren't a mermaid because mermaids don't work computers, because they will get the computer wet.