Thank you

One of my autistc students does not speak or respond to questions often. She will usually sit in her seat when I offer her Hello Kitty stickers. She wants the whole sticker page though, so she gets mad when she only is offered one or a choice between two. Eventually she will take one when I say, "Ok, then no sticker," but be angry about it. Today I gave her a sticker for sitting in her seat and she said, "Thank you!" I almost cried.