The upper age limit of reproduction for a female Giant panda appears to be 21 years. A few pandas have reached this (including Bai Yun at San Diego Zoo); though I'd imagine most, like Bai Yun, had a strong reproductive history leading up to that final birth (i.e. first births at 20+ would be unlikely). I hope the contract is renewed; though if they stay another 5 years, then Funi returns to China as an 18 year old and then gives birth almost immediately after a decade of failing to breed at Adelaide, that will be a little embarassing. Hopefully a 5 year extension will give both Funi a chance to experience motherhood; and Adelaide the success they're working so hard for. The first birth of a Giant panda in Australasia would be a very special zoological achievement.