Something is not adding up...

I'm 30 years old, 4'9" and 94.6lbs (yesterday). I eat all organic and indulge in organic dark chocolate 1x per week (portion control). I work out 3-4x week (body rock). I have a butt. It will never go away and that's ok bc my husband loves it. However it has a slight jiggle to it. Especially noticeable in bikinis and, of all things, maxi skirts. What's up? I'm embarrassed to go to the beach and think that I'll stick to fully lined pencil skirts. What am I doing wrong?