In my experience, no. But there's a chance depending upon what some of this context is.
Blowing smoke in your face: Without the context, I assume that this is because she doesn't really think highly of you, but then again I don't know if you were both smokers or if it had to do with a joke, or if she didn't mean to, etc.
Giggling to friend: If a girl is whispering about you to her friend and giggling, in my experience it's not a good sign.
Her being Awkward: In my experience, if a girl is awkward (even if it's her fault), then she thought you were awkward. Which is a no go. But she talked to you the other day regular, so maybe this didn't matter.
Staring at you as you leave: This is the deal breaker. If she was looking at you as you were leaving, then go for it. But if she was staring at you because you were staring at her or because you kept looking back, then chances are it doesn't help your case.
If you have the feeling that her thoughts and impression about you are positive, then go for it.
Also, if you guys are like 14, then most likely she'll say yes regardless because all 14 year old girls are looking for status. Which means they want a good looking boyfriend so they fit in or whatever it is they think on why they *need* a boyfriend.