Lulu Looks Confused...

She's asking herself why tried to 1v5 the enemies under their turret.

Didn't taste like purple

It's the first time she tasted purple.

Wonders what we were doing and why.

She is wondering why Shyvana rage quit https://static.lolwallpapers.net/2014/08/Lulu+Shyvana.jpg

enemy ashe tried to kill her with hawkshot

Something didn't taste like purple?

I'd say it's because the eyes are completely open, giving the impression she raised her eyebrows, which is a common indicator for surprise or confusion.

She's wondering why she's still a mediocre champion.