I Totally Outsmarted My Siblings With Our Family Game Night Rules Change

So here's the deal. Every Friday night my family has a mandatory game night. It's just me, my older brother who acts like he owns the place and is always trying to get the best of everyone, and our little sister who thinks everything is a competition but secretly gets all competitive because she's actually good at most things too. I'm stuck in the middle, getting squeezed by both ends - feeling the pressure from above and wanting to keep up with the bottom. Anyway, my brother always makes sure that there are no rules or limits when it comes to betting game prizes (we're talking about candy and such here). Last week, as we were setting up for game night, I suggested we should make a rule that you can only bet what you actually have on hand at the start of each round. My brother looked at me like he was going to challenge this but then he got all quiet. See, earlier in the day I had hidden his favorite type of candy and swapped them out for our little sister's stash without her noticing. So when it came time to bet, I just pulled out my cache knowing exactly what I'd taken from him. My brother went into a rage - shouting that I'd cheated but really he was fuming because he couldn't prove anything. The night ended with him glaring at me and our sister thinking she won the big game, all thanks to the clever rule change and my sweet little trick. But now here I am, feeling guilty for using underhanded tactics even if it does mean having more sweets. So is this normal sibling rivalry stuff or should I just apologize and make things right? What do you guys think? Am I really that much of an asshole?