Climbing Mt Fuji with children 14 & 13y?

We are travelling to Japan in July. We would like te climb Mount Fuji. Is it allowed to do it with children? Our daughter is 14 and our son will be 13 soon. They are both very sportive and are used to do adventurous activities with us during our travels.

Yes, it is allowed - I know someone that took their kids up Fuji when they were quite small. There are some good online guides around so do some research first regarding preparation, what to take and what to expect.

The nursery school in the city where I live seems to climb Mt.Fuji almost every year.
https://youtu.be/0QBSX3hxqno
So if you're that age, you can climb.
In my case, altitude sickness was the most difficult part, so please climb slowly and drink plenty of water.
Depending on your physical constitution, some people may not get altitude sickness.
By the way, the higher you go, the higher the price of PET bottles, but please buy it even if it is expensive.
They also sell oxygen cans, but I haven't used them, so I don't know how effective they are.
The weight of the luggage also consumes physical strength, so it is better to keep it to a minimum.
The summit is very windy, just like in the middle of winter, so please take measures against the cold.
It didn't rain, but I recommend wearing Gore-Tex mountain climbing wear. Choose waterproof hiking shoes.

By the way, before I climbed Mt. Fuji, I climbed Mt. Oyama and practiced mountain climbing.
I think it's better to practice walking and climbing mountains on a daily basis.