The words that the author used here give the reader the idea that the Queen is something truly extravagant. I'm guessing that something strange happened, making Alice "wonder a little" about what happened, but she was quickly enraptured by the Queen to put much more thought into the matter or to not believe it outright. I'm assuming this sentence is from Alice in Wonderland, and if you were to go further, you'd notice that Alice almost always notices and challenges the strange things happening in Wonderland. She knows when things are not as they should be, and little can distract her from that fact. Now, knowing that she let go of the thought that something wasn't as it should be, gives us the idea that the Queen was very powerful and mighty, making Alice believe in the untrue. At least, that's my understanding of it.