#i calculated it and this means theta & kos would be physically 14 when rock murder takes place which makes sense

[snackleggg]

Anyway, here's how I headcanon timelord ageing works.

Only applies to their first body:

From when they're loomed until they are age 8 they age like a regular human

At age 8 their ageing slows down to around 15 years equalling 2 years of physical change (this isn't because of the schism, its more that this is the age they look into the schism bc of this being the point of slower aging)

This continues until they physically reach the age of around 40, then their ageing picks up again to be probably only a little slower than that of a human (every 2 years would be 1 year of physical ageing)

Post-first body ageing:

Every body after the first gains longer and longer "life span" so to speak (which means how long they can have that body before succumbing to "old age" would get longer with each regeneration, even if they regenerated with an old body)

Similar to the first body, after a certain amount of time the body's ageing will started rapidly increasing in speed