The Little Schemer is a playful introduction and SICP is more impactful but also more challenging book. Even if you already know how to program, it will force you to re-wire how you think about programming.

SICP is great at teaching concepts and testing your knowledge, but it lacks an important part that is not quite obvious at first: Interactive programming AKA how to actually use a Lisp.

I recommend you watch some videos of people using an IDE/Emacs or some text editor with sufficient support like VSCode to write Lisp code interactively. How they build a program while it is running. But also doing mechanical things like navigation and structural editing.

Step 1 is the basic mechanics of that, leveraging an integrated REPL and language constructs. Step 2 is to make this productive and fluent, by using workflows, tricks and tools that let you introspect what is there, manage program state, move things around effectively etc. Step 3 is then to go beyond and not just write the program in a direct fashion, but experiment, generate data, visualizations, interactive debugging etc.