In "Pardon my Past" when Phoebe gets out the family tree, it says Penny Halliwell died in 1968. That would have been before her grandaughters were even born. And when Paige put on Penny's red boots and went back to the past, she went back to 1967 and Penny was quite young, but we see that she died as a quite older woman. Did she age that much in one year?