Okay having read this through, I assume we're meant to think that Sonny is kind of awful and an idiot who never thinks about her actions, doesn't pay attention to the world around her or other people because she's so wrapped up in herself, and is not just an opportunist criminal, but somebody with compulsive stealing habits who will steal things even when it's a really obvious setup?
It's a bit of a rough sell when the first chapter doesn't set up any sympathetic traits for the protagonist of the story. It's not impossible, and maybe if the artist draws her in a way that really highlights that she's a fun character, it can work. I was surprised by the lack of any sort of twist where the protagonist knew about the setup all along, or that it wasn't the obvious setup it seemed like. Maybe it'd feel a bit better if the Manager doesn't carry popcorn out of the room, he just appears with it later, so it doesn't feel so obvious he's planning to watch something. It might also be better if he gives a flimsy excuse for taking her on in spite of her criminal past, because he takes her on so unquestioningly that Sonny looks like an absolute fool for not being suspicious of the situation (unless that's the point? That she's an idiot?). Perhaps adding in something like "you're a liability, but the government is paying me bank to hire you" or "I know I shouldn't hire you... but you remind me of me when I was your age..." would just ease that a little? Either that or have Sonny comment on it to the audience as he leaves the room, "Well, this is an obvious trap. The popcorn is a bit much, old man..."
The final line "Better than an amateur, but not as good as a pro." is a bit weird. If you're not pro standard or working as a pro, then you are, by definition, an amateur. Maybe try making it more specific and more condescending like:
"Not bad for a small-town burglar, but too sloppy to go pro. Don't worry, kid, we'll whip you into shape."
Adding something on the end about intentions to train or employ her also sets up intrigue for the reader to continue reading.