Six days later, by the following Wednesday evening, she was able ~~~. what does it mean?

Question

From then on, every day after school, Matilda shut herself in her room and practised with the cigar. And soon it all began to come together in the most wonderful way. Six days later, by the following Wednesday evening, she was able not only to lift the cigar up into the air but also to move it around exactly as she wished. It was beautiful. "I can do it!" she cried. "I can really do it! I can pick the cigar up just with my eye-power and push it and pull it in the air any way I want!"

Six days later, by the following Wednesday evening

what does this sentence mean??

Answer 1

The author he was being a bit redundant. The idea is that something happened, and then six days later something else happened. But the author also tells us the same information in day and time: Wednesday evening.

Answer 2

She started practicing on Thursday after school. Maybe Dahl tells us that, maybe he doesn't and expects us to understand that ourselves. Six days later takes her to Wednesday evening. (The exact days are probably not important.)