I'm going to pursue my friend even after she's said no
Why would you continue to pursue her?
She said no today because she has a boyfriend but yesterday she had said yes.
You shouldn't pursue someone that isn't interested, even if you feel like they are sending mixed messages. If your friend is dating someone, talk to her and tell her why you're confused by her actions and then respect her decision.
Why not, I was the only one pursuing her when she had a boyfriend. I don't want to lose her over some dipshit. I don't care about that loser.
It really doesn't matter what you want, constantly asking someone out is annoying and creepy. You should stop making her uncomfortable.