@the idiots
I'll break it down, why scout? It was already introduced that she underestimated him; It wouldn't make sense for her to be cautious after doing that.
EVEN THEN, she still sent in the clones first instead of sending in everyone, which proves she's pretty good strategist despite that ego. When the attack fell she went in to scout to see what happened and the scene shocked her long enough for more soldiers to check up on her. That mistake was Rosalitte, not Stolas, but as a scout it at least showed her what had happened.
With that it presents 2 options: surrender or go defensive which was the best choice. Because she can't surrender... She was the one who insulted him in front of everyone; To give up after the first charge is A LOT worse than losing, making her also look pathetic. There was also the struggling she had to deal with during training and discouraging words of her master. And finally, her contracted demon's expectations that she placed upon herself: "Someone they can be proud of, never losing to anyone, to become a great demon king for them." That goal was to win, going defensive could of been seen as cowardly as she would be seen as backing down from the floor(s) challenge of the person she called weak.
"testing out wind wall effectiveness," or "using wind wall in the beginning." You guys assume any of her demons can use that ability but as far as we know only Masamune can. And we can assume Solas can too cause you think Solas can too, being a Wind Demon King. But if that was the case, why not double cast wind wall on Masamune?
@Gaigous said it best.