When I started schooling, parents used to send kids to school at around 4 years. Now, kids see teachers as early as 1 and half years of age. This is ridiculous.
We did an experiment and sent our youngest to school when she was 5 years old. She was home schooled using some apps and books - in her own time and depending on her mood. Now, her teacher says she's one of the brightest in the class, a quick learner filled with creativity.