What stands the number of years?
Sanemi's age remains unknown.
Sanemi's years is said to be around thirty years old.
One option is that Sanemi's age could be in the late twenties.
There is discrepancy in the sources regarding Sanemi's age.
While we may not know his exact age, Sanemi has proven himself to be a formidable force.
Sanemi's commitment to his purpose remains steadfast, irrespective of his age.
All in all, even though we may not have the exact age of Sanemi, his exceptional abilities, unwavering dedication, and commitment are evident.

Demon Slayer Character Guide Ages Heights and Birthdays CBR