What to do to get sexy fit?

I want to get fit and eat healthy I am tired of being over weight I have hypothyriod cause I got it removed last year and is 5'7ish and weight is from 220 to 228 it bounces a lot. I don't talk weight much with people but when I tell them how I weigh they are surprise they say I caring it good and don't look bad. And I am 17 when I suck in my stomach one can see the shadow of a six pack barely. I want my senior year to be the sexy chick and feel good about myself instead of the "oh your cute...average chick to below average chick. " I know I won't get results over night but I will with time but I am hoping if I got fit maybe I can inspire my parents to do the same but Idk even know where to begin on my jounery can I have some guidance? What to eat what exercises to do? Would seventeen magazine exercises help me?