Don't worry about it, we're all taking it slow right now.

Both works, so it's your call whether she comes in late or was there the whole time. If she just started today(IC), she would be one of the  replacements for earlier casualties and arrived earlier during the day, due to the road being highly dangerous at night. I'd say you'll get more out of her introduction by placing her as the new gal, since she will do a lot of reacting and catching up.

Also, do you use the same name for other characters?