I bought the Flirty Girl Fitness dvd and when i do it,it feels like my azz is burning off?

i mean its so hard to do and they said ist going to be fun(although they do joke a lot and it makes me laugh),but still there is no dancing in it????only aerobic that r soooooo hard to do and im already obese and i wanna burn fat and lose wight...what do i do?