I Spilled the Beans on My Little Brother's Surprise Party... Sort Of

So my little brother is turning 10, and he’s such a fan of surprises, we decided to plan this big party for him. But here’s the thing... I kinda sorta gave it away a bit. See, a couple days ago, when mom was driving us to school, she mentioned picking up balloons from the store that day. Now, you wouldn’t think it’s much, right? Just some harmless hints about balloons. But then my brother asks me in the middle of the night what I saw at the grocery store earlier, and I just... let a little slip. Oops! Of course, he denies everything even though his eyes are practically bugging out of his head with curiosity. And here’s another thing, my mom knows that I know about it, but she’s not telling him to stop planning until after the party. So yeah, technically I didn’t tell him, but I’m pretty sure he knows something is up... It feels a bit petty now thinking about how much I really wanted to surprise him, but oh well, can’t go back in time!