Is being emo a good thing?

Being emotional is a good thing. Being 'emo' in the sense of suicidal however, isn't.
It's all about how you see it. If it's a scene you want to involve yourself in, go for it.
All I can really tell you is to make sure you're ready to dedicate yourself. It might not seem like a big deal, but 'emo' kids get a lot of grief.
Good luck!