I have a wii fit question about my mii.?

Awhile back I created my mii on the wii fit. Now when I get on these last couple of times my mii looks different. How can I change that. When I go to the plaza are parade it still looks like the same one I first created but when I go to do the wii fit, my mii is different. I can not figure out what happen, but I would like to get it to look like my mii when I first started on the wii.