[sa retournée -> s'est retournée
--> sa is a possession article; s'est (se + est) is the reflexive pronoun + verb you're looking for.
regarda autour d'un peu plus -> regarda autour d'elle un peu plus
--> She's looking around of herself; or you could always just say 'regarda aux allentours'; she looked around.
exclamée -> s'est exclamée
--> You need the s'est there. Another correct form would be s'exclama; but this is barely used at all anymore, unless you're really fluent in written French.
es-tu recherché -> cherches-tu
--> Hee! Lavie, what you wrote is used for criminals. XD Someone being 'recherché' means they're wanted by the authorities.
elle a posé -> elle a demandé
--> Posé is used for posing (as in, posing for pictures). You would also say 'posé une question', but in that case, you have to mention the question part.
Beyond that, I don't see anything wrong. c8 ]Mathias s'est tourné la tête alors qu'il attendait que Nicole se retourne. Il comprit tout de suite que la Choopa ne le voyait pas. Il essaya d'agité sa queue, mais ceci n'a pas aidé vraiment.
— Par ici, il siffla, essayant d'indiquer sa position à Nicole.
Après quelques secondes de confusion et une Choopa qui regarda autour d'elle pendant un moment, Nicole a éventuellement remarqué Mathias, par terre. Pour la saluée, Mathias a agité la queue.
— Ce n'est rien, il assura Nicole. Beaucoup ne me vois pas à cause de ma petite taille. Effectivement, je cherche un verger de pommes. Je...
Il s'arrêta lorsque Nicole à ajouté qu'elle cherchait un verger elle-aussi, pour cueillir des pommes pour une merveilleuse tarte maison. Le Nagi s'est léché les lèvres à l'idée de manger une si bonne tarte.
— C'est parfait! J'ai une recette pour une tarte maison, moi-aussi. Voudrais-tu cueillir des pommes avec moi, alors?
[ Mathias tilted his head as he waited for Nicole to turn around. He immediately understood that the Choopa couldn't see him. He tried to wave his tail, but it didn't really help. "Over here," he hissed, trying to indicate Nicole his position.
After a few seconds of confusion and a Choopa who looked around for a moment, Nicole eventually noticed Mathias on the ground. To greet her, Mathias waved his tail. "It's okay," he assured Nicole. "Many don't see me because of my small size. Precisely, I'm looking for an apple orchard. I..."
He stopped when Nicole added she was also looking for an orchard to pick apples for a wonderful homemade pie. The Nagi licked his lips at the thought of eating such a tasty pie. "That's perfect! I have a homemade recipe, too. Would you like to pick apples with me, then?" ]