I feel like she's glaring at me for not knowing who she's cosplaying as... A glare with a pout combination from a cute girl can be quite deadly to die hard otakus as far as I know.
And I know that I've seen here somewhere before, but it's at the tip of my brain! So if anyone recognizes this blonde, female character with a huge, red bow on her hair, please feel free to leave a comment and let me know! Links to references are welcome!
EDIT: Thanks to Sheik-chan for letting us know this is Launch from Dragon Ball!