I think you need to have 10(?) posts before being able to change your avatar. I believe this is to cut down on spammers
Well welcome by the way, and from your username, the first thing I was reminded of was パチュリー, ウッ!
Although I'm not too sure if you can read that. Don't look it up. I wonder how many people actually get it based on my weird hobbies.
Still, welcome welcome~