I don't think having an avatar from an anime is worth getting called a weeb over. That's more of a word that's better left to describe their personality/actions. Your avatar is generally just something you like, something you can relate to, or something interesting in some way to you. If I set Disgust as my forum avatar, it doesn't mean I'm a die-hard Inside Out fan; it just means that I found the character from the movie interesting enough to identify myself with it.