An occasional review will focus on this point. Alice in Wonderland is no more children's book than, "The Lord of the Rings".
The reason this five star book gets less stars occasionally is not because of its contents or purpose; it is because of either being mistaken for a kids book, in which case one wonders why it is forced on kids, or it is so dated that even the reader thinks it is gobbledygook.
You will find the book full of references to items of the time and play on words of the time.
If you fall into either of these categories then you need to first purchase "The Annotated Alice: The Definitive Edition"; this will clear this understandable confusion. Be aware that every sentience is a play on words for a jab at the culture of that time.
I will not go through the story, as that is why you are buying this book. However I will say that it is a classic and should be part of everyone's cultural education.
When you make it through this book and enjoy it the next challenge should be "Alice's Abenteuer Im Wunderland” German Translation.
If you are also interested in sci-fi then try to get a copy of "Mimsy Were the Borogoves" by Henry Kuttner.