Not worried about it not having El Capitan, just want the battery to last (she is not good at noticing if there was something wrong with the battery). The box looked kinda dirty on one end So I imagine that it may have been in storage for a while.
I'll probably wait to put El Capitan on it because I have to leave tomorrow and I'm just getting things set it for her now (and the internet here is like 2Mbps so even basic updates are taking a while). Do you see a reason that she needs to have El Capitan on it? It may be a while before I'm back.