How do i tell my mom nicely i dont want her doing my hair for my birthday party?

SO my party is next month and my hair stylist told me for 25 dollars so would do my hair for my party! Its an alice in wonderland theme so i have a silver dimound flower head band and i want that a poof in the back and curls and i want her to put sparkles in my hair so any ways ill pay for it but my mom says she will do my hair its just i cant afford mistakes!! And i know with a hair dresser she has to make it work what should i say?