Speaking of context, you referred to the line--in isolation--"The answer is no." Here, again, is the line
in the context of the song (with other sections redacted to make the point:
I ought to say, no, no, no sir. At least I'm gonna say that I tried...I simply must go. The answer is no....But maybe just a cigarette more.
She very clearly has stated that she
ought to say "no, no, no, sir" and leave--meaning she doesn't
want to, but society is pressuring her to (as is immediately confirmed by her next line and the subsequent ones I omitted for brevity where she goes on to define exactly who is expecting her to say "no, no, no sir"). I
ought to say "no," or at least I'm going to say that I did and leave to appease my family and the neighbors (i.e., society). So she does say it, resolves to go, but then decides to stay for "just a cigarette more."
So she is not saying "No" to stop anything that is happening against her will (as nothing is happening yet); she has stated that this is what she is expected to say so she's saying it in order to say that she did. It is clearly not what she wants, however, as again evidenced by the lyrics. This is not an
interpretation. This is self-evidently true.