Alright, bro. Congrats on your first night out of sarging

.
Here's something that you need to know: some girls act like they are better
than they really are. Like that 8 you were talking to was acting like a 9 or
a 10. You need to calibrate (something that comes with experience) with the
negs. So even though she was okay looking, you needed to treat her as
though she is really pretty (as in negging her a bit extra and showing more
disinterest that usual).
So if she said: "What makes you think we're average?"
I liked your reply. But I would have said something more along the lines of:
PUA:"Wait...are you the president's daughter?"
HB:"nooo...."
PUA:"Then you're average unless you can prove me wrong

"
And that's a neg. right after the neg, you need to get right on with the
routine. DON'T LET HER RESPOND to the neg.
So, it should have been like:
HB: "What makes you think we're average?"
PUA:"Wait...have I seen you TV before?" (Say it as if she seems familiar).
HB:"Nooo...."
PUA:"Then you're average

, but you can try to prove otherwise

"
PUA: "Like I was saying, my buddy over there..." and continue.
I would have used that opener on the obstacle after that HB said "What
makes you think we're average?"
And A response to the "You're just trying to talk to us" line would be:
"Hahahaha, there are 100 other girls in this club, I could have talked to
any ones that I chose. What makes you so different from them?" (said in a
playful tone and a smile).
Then you can either let her respond, or continue with the story before
she says anything. Again, try to direct the opener towards the obstacle
first and then work in the target.
For future reference, I would change openers, or just take out the neg
part of the opener...unless she's a 10. Remember: Calibration.
Hopes that helps, man

.