The feeling will sure be neutral? 
Reality is, people form impression of another person in seconds.
I've met people who I dislike immediately (and who dislike me
immediately) for no rhyme or reason.
It's hard to read the body language of women, but here's a
tip:
Observe her expression and body language when she is among her
friends and people she likes. The way her eyes brighten up and
laugh.
When you approach her, check if you see a similar body
language.
If she is looking all over the place, avoiding your face, no matter
how polite she sounds - FORGET IT. She doesn't like your
look.
If she is looking at you with a neutral face, smiling very politely
- TOUGH. She is not impressed.
If she has the same delighted expression - A NARROW CHANCE.
If she seems warm and is maintaining the conversation with you and
it all seems too easy to be true - GOOD CHANCE.
Actually the last two scenarios are very low probability, but you
already know that. 
