Kids 1st Birthday Ideas

I was wondering if parents chose birthday themes that they like or ones that you think your child may like for their 1st bday party? I love Hello Kitty, but my family and friends didn't think that theme was appropriate for the 1st party. They suggested maybe for an older child's party but not for a 1 year old. So what do you all think? Is there an age for what themes should be used?