Not really. In the comics, Groot has more than just 'I am Groot' to express himself. His character is developed with a broader vocabulary to fit different storylines and scenarios.
You can try looking in local comic book stores. They usually have a wide selection of graphic novels, and there's a good chance they might carry 'I am Groot graphic novels'.
Yes. It has simple yet engaging storytelling. The art style is also very appealing, which can draw in beginners easily. Groot is a well - loved character, and the graphic novel gives a great opportunity to explore his world in a new format.