the Proposal

I'm only up to Episode 9 - and this could be the last one i watch, as it's not necessarily a bad show, it's just not good. (and that's not just comparing it to shows on at the moment, but previous shows some of the cast have been involved in).

So they invent a medical disorder (which I have no problem with) just to say she has perfect recall and no inhibitions. But what I don't get is that when she was proposed to she needs time to think about it?
As she stated in the first episode when questioned about Eds death she stated "the moment i saw him it's like he's always been dead." So surely the moment she'd been asked to marry Liam it's like he'd always asked her and she would be able to process all the required memories to respond - plus if she'd ever thought of being proposed to, she would know how she'd want to feel when asked.
And as she has no inhibitions to question and comment on anything she would have no problem saying 'no' immediately.

So what i don't get is why it would take so long (days/weeks) to give an answer.