You clearly don't understand context clues.
I wrote that it was boasting it because it was to me (and later as it turns out to be true) a full out farce, a calumniation, a fabrication, a deception, a lie.
She was perpetuating that she was 21, and to some, lying about their age can be a sense of endearment for themselves or from their peers. Some people love the fantasy that getting older somehow changes things for you. Boasting it is to be saying: "look everyone, I'm 21. I'm older than you."
You see, I was doing something called "reading into it." Sure, it was all assumption and my assumptions could be wrong, but based on the statements that come right after the first, you can clearly surmise that I was using boast to convey that I was calling her bluff.
