Готово is pronounced like гатова. As a rule, an unstressed 'о' is reduced to an 'а'.
The same is true for unstressed 'е' which tend to be reduced to an 'и'.
Its played havok on my listening and speaking for two years now. I hope you have better luck than me!
Only if you are of the neuter gender, and then it would be "я готово" with three o's. If not, better say я готов or я готова, depending on your genuine gender. PS: I hope I've got this right, I haven't been studying Russian for very long.
I am prepared/I am cooked? я готовлю суп. I am readying the soup? I love Russian!