Should I let this opportunity slip away?

Okay, I know this isn't a big deal, but... I applied for a job at a school supply store (a new store, opened less than a year ago, and I think they'll be really busy in the few days leading up to September 21st). They told me I could come back this evening to ask the owner, so I'd like your advice: should I go for it? Especially since I'm still in high school, and there are only three weeks left before classes start, which means I'd be working for less than a month. Will I even be accepted under these conditions?

I really need your helpة I don't want to regret anything later.