Permanent Visa Question

My mom and I are planning to stay in japan for good. I've been recognize as a child of a japanese and will be granted a "Child of Japanese national" Visa. I'm 18 years old and someone told me that my mom wont be given a visa because I'm already 18(legal age?), is it true that I can't give her a visa? or she wont be granted a visa?
and if she's granted a tourist visa,
can she have a permanent visa?
how?
my mom and dad aren't married and my dad already died.

please answer
answer will be very much appreciated.

Your mother may have to obtain citizenship in Japan, which depending on what country you are from, may mean renouncing her current citizenship.

Contact your local embassy office or consulate and they can further direct you.

Your mother is not your dependent, so she can't get a visa through you no matter how old you are.

Who was the Japanese national- your father? If so, I'm afraid your mother will have to qualify for a visa like everyone else- working visa seems the most likely, but only if she has graduated from university, as a bachelor's degree is the minimum educational requirement.

What are you planning to do for income in Japan?
It's unlikely that you as an 18-year-old can earn enough to support two people, even if your mother is able to get a visa to stay.

Citizenship is not an option for people who have not already lived in Japan for many years, unless they have Japanese ancestry.

I don't think it's beyond the realms of possibility that your mom can get a visa based on her relationship with you. You should ask the immigration office in Japan instead of asking here.