...I Messed Up Big Time in Front of Everyone...

So...today at lunch I was with my older brother's friends and I just couldn't help but feel like they thought I was a bit immature. So, to prove them wrong...or maybe just because I was nervous about what they thought...I started talking about this really embarrassing childhood memory of me wearing a silly costume my parents made for Halloween. And now everyone thinks I'm just that little kid from the past, not the teenager trying to fit in with older friends....What do you guys think? Is it normal to feel like you have to overcompensate when you're trying to show your maturity level? Any advice?