Thanks for your comment and kind words Ankit!
I had my own struggle with German ahah, I took a lot of classes throughout the years but never quite managed to reach a level where I can hold a proper conversation. The fact that most German speakers I met were also fluent in English didn't help.
I think your idea to learn with children's book could be good yes, I did try to do it in Japanese with simple illustrated books and it helped to an extent. The difficulty in German for me was always the structure of sentences and the conjugation, so I'm not sure these books will help with that, but it's worth a try!
Best of luck with your German learning and thanks again for stopping by!