Why women allowed to climb Mount Fuji earlier in the years?

This statement isn't entirely true. There was in fact a restriction, that prevented women from climbing the mountain for around 1000 years.

According to the Shinto religion, which plays an important role in Japan, Mount Fuji was considered to be a sacred and mystical mountain. Religious tradition dictated that the presence of women during certain times was considered to be harmful to the spirit of the mountain and would invite unfavorable circumstances.

However, in 1868, the Meiji Restoration marked a significant turning point in Japanese society, fostering change and modern reforms. As a result of these changes, the ban on women climbing Mount Fuji was finally lifted, allowing them to ascend the iconic peak alongside men.