Ah, ignore her.. as you say, she doesn't know you well enough so why are you even listening to her? I doubt she was trying to be rude to you, probably just doesn't realise!
i agree the most innocent of questions can really hit hard when ttc. i'm sorry you had to deal with that woman.
i get asked all the time 'so when are you going to have a baby' by ppl at work and by OH family. i really feel like shouting 'i don't know WHEN i will have a baby. i'm trying as hard as i can!!' before we were ttc this question didn't bother me but now - grrrr