My twin brother and I always used to be topless at home all day when we were kids, but when I started growing breasts I got shy (like all girls that age, I imagine) and stopped. I came across the idea of topfreedom ("If men can be topless, why not women?") when I was 16 and since then I started doing it again.
I also got rid of all bras and bikini tops, and I still don't own any. So there's no way you'll ever see me on a beach without me being topless! When the weather's hot, I'm the same way at home -why sweat more if I can help it?