I understand the issue with age as our bodies degrade after we reach our peak in our twenties to thirties, but jill doesn't really have that problem yet. Yes she's 50, but thanks to her encounter and curing of the nemesis strand of T - virus, her aging period has considerably slowed down, in resistant evil dead island which is set in the middle of 6 & 7 with a 2 year time gap both ways, it is set 13 years after resident evil 2 & 3, Claire had aged, leon had aged, but jill had barely aged if at all because of beimg infected and cured of the nemesis T - virus strain. Similarly sherry birkin, was infected and cured of the G - virus in 2, and shown to have gained a regenerative healing factor from it in 6 after beimg stabbed. So jill most likely wouldn't be as physically degraded as Chris or loen would be.