No, she didn't have a "theme" at that age really. But that is around the age when she started asking to do things to change up her room. She wanted her walls painted (from violet to black... uh.. no. Pick another color. She could never decide on one, so it's still violet, but now, at 14, she's thinking blue and brown). She added posters of Lord of the Rings, Superheros (big, big Marvel comics fan), and left the drawings she did as a younger person. She/we ditched some of the more little girl styled furniture right after Christmas this year (at 14!) and upgraded to more cubicle style (with the pull out bins), which is what she wanted.
I would probably not worry too much right now, but maybe look ahead to another couple of years and plan to re-do things then, when her more mature self will want it really different than what she thinks she wants now (at 10). Because it Will change.
You can do more modest/subtle/inexpensive changes now, though. And maybe change them again later if needed. A new quilt/bedspread. A new set of drapes/curtain. Add a more teen styled chair (our daughter got a bungee chair around then). Have her clean off her walls and only put back what she wants (store/save/take pictures for posterity the rest). Clean/clear off the dresser completely, and decide what she actually wants back, and what can be garage saled or donated. And so on.
But major furniture changes and paint... I'd probably wait another couple years.
But oh... the biggest difference is it went from semi-organized/controlled mess to a complete disaster 24/7/365. Complete with wet towels on the floor every morning that I have to fuss at her about every day.
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After reading the other responses, yes! My daughter had a boat load of stuffed animals (around then we got under bed storage and put them all in there and under the bed). And her computer tower desk was covered with arts/crafts/boxes that she had made, decorated or assembled. Every nook and cranny, and then some. One corner has her keyboard in it and baskets of music books. That is still there. Only now she's added violin, ukulele, flute and clarinet cases....
It's a work in progress, like she is. :)