She could come in anytime now although 6 to 10 mo is more common. Unless there is a pressing reason to spay her, I would wait and spay her 3 mos after her next season. Make the appointment while she is in season so that you do not forget. Watch her well at all times while she is in heat. Do not leave her out alone even with a fence or a dog run. No time alone in the yard or off lead in public even for a single moment!