See there no such restrictions in terms of Japanese Language Interpreter. But if you see the vacancies notification in any of the site then you will find out that for most recruiters the focus is on the experience in the job. Apart from this there are some recruiters which can create restrictions for Fresher Interpreter within age 35-40. So if you have experience, you have nothing to worry. But if you didn't have experience, then it would be better for you to apply with in 30-35 years of age for maximum opportunity.

To know more about Japanese Language visit the link below:

https://www.careers360.com/courses/japanese-course

I hope this answer helps. All the very best for your future endeavors!