I'm right there with you. I collect signed memorabilia, and I still get awestruck meeting guys like Magic, Gordie Howe, Montana, etc... I'll wear a jersey to games for all my local teams. I know it really accomplishes nothing....but it still makes me feel like I'm doing my part to support the team.
As far as worrying that it looks "child-like'.....fortunately, my self-confidence allows me to not give a f**k what some other "dude" at the game thinks of my attire.
As far as worrying that it looks "child-like'.....fortunately, my self-confidence allows me to not give a f**k what some other "dude" at the game thinks of my attire.