Cool, she didn't have any plans. That was good...

Actually, that was a good question. Why did he ask her? It had popped up in his head and he acted on instinct, but now that he stood there, with her staring at him, his momentum dampened, and he hesitated.

"Uh... well..."

Come on, man, you can speak better than this.

"Actually, Lavender is going to enter the contest, and I wanted to let you know."

No, come on, don't leave it at that, man. That's super awkward. Say something else...

"...and also, uh... I was wondering if you wanted to go... together...?"

Nailed it.