Whens to old?

Recently Andy suggested we get Issy a little more stylish and not so smothered in character stuff like hello kitty, Minnie mouse etc as he's concerned she may get bullied at school, Everyone has the usual black/navy coat, biker jackets, parker jackets and generally really cute stylish coats and there's our little Issy in a pink coat covered in hello kitty's. It's cute but of course having your child bullied is every parents worst nightmare. I'm terrified she may start having other kids call her a baby or comment on the fact her clothes are a bit babyish at times but at the same time I want her to know if she likes and she's happy others opinions really don't matter,  I know shops sell character clothes for older girls but they have more of a stylish design to them and aren't so child like, Of course I don't want to take her childhood away and make her grow up to quickly either, I see plenty of other little girls the same age as Issy looking super cute and very stylish with their little bun doughnuts in, big bows, little bags etc

So I'd like other mummy opinions are we panicking to much? 

she will be 6 in January

I think we should opt for the more stylish designs of characters and not the so toddler looking designs which fixes the problem altogether she's not having her childhood ripped away, she's stylish and she's happy