I agree with Ivy, if your starter was younger then by all means use a more recessive eye, but given her age I'd also look to make a sibling pair from a nice 9T cat with a dominant eye and try to get her to pass it as hidden then breed the siblings together. She certainly seems happy enough to pass it though so hopefully won't be too long before you get something you can breed. You can always pop the first hider straight away and pop with a MM then if it hasn't passed by the time a sibling is ready to breed swap to a sibling breed and get yourself a pure eye