That sounds a nice memento of Home Guard auxiliary service. Does it give any further detail of the unit joined? Or dates? The age range is certainly OK and, just like their male counterparts, women served with ages of between 17 and their 70s, more or less officially.
The linked summary of information about the auxiliaries posted by Radiorails gives a good indication of the function of these women. A number were, in addition, given training in functions a little closer to the battlefield including rifle shooting, although this was unofficial.
I have online quite a nice memory written by a member of the Aldridge battalion auxiliaries - 32nd Staffordshire (Aldridge) Battalion. Worth a read to give an indication of the atmosphere, practices and attitudes of the time. It's here:
https://www.staffshomeguard.co.uk/HomeGuardingPages/63staffshg.htm and it's safe to click on.
Chris