I've been working as...,

[Silverobama]

I was talking with a group of friends at an English club. I was talking about myself working as tutor. I said:

I've been working as a tutor for 12 years and I think I'll be continuing to do that for the rest of my life.

The intended meaning is "I already worked as a tutor for 12 years and will do that till I die"

Is the italic sentence natural?

 

[emsr2d2]

I was talking with a group of friends at an English club no full stop here I was talking about myself my working as a tutor. I said:

I've been working as a tutor for 12 twelve years and I think I'll be continuing continue to do that for the rest of my life.

The intended meaning is "I have already worked as a tutor for 12 twelve years and will do that till I die".
Is the italic sentence natural?

See above. Don't forget to write numbers from zero to twenty in words, not digits.
Your sentence says what you want it to. Are you not planning to retire at some point?

 

[Silverobama]

Are you not planning to retire at some point?

People, especially teachers, still teach after they have retired because they can earn money. For me, I learn things from all of you when I teach, and I share what I've learned with my students and friends.

 

[emsr2d2]

People, especially teachers, still teach after they have retired because they can earn money. For me, I learn things from all of you when I teach, and I share what I've learned with my students and friends.

Anyone can keep working beyond retirement age if they want to keep earning money. It's just quite unusual for someone to plan in advance to keep working until they die.