In your case, since your husband's
paternal grandmother passed away, your family falls under the
paternal descendant line - meaning, yes, the connection is there, but you are not the immediate next of kin like her son (i.e., your father-in-law) or grandson (your husband).
Now let’s break this down clearly:
1. During Karyam (up to 13th or 16th day):
As you rightly mentioned,
no pooja,
no abhishegam,
no lighting of deepam in your puja room. Even regular sandhyavandanam and nithya karma is done
without Deepam or any loud mantras. You’ve followed that correctly. That period is called
Ashoucham or
Theetu.
2. After the Karyam:
Here’s where confusion usually starts. The Shastram makes a clear distinction based on
varisai (succession in the lineage).
From your message, your husband is the
grandson of the deceased (not the son). So your family is
3rd generation from the deceased. As per tradition:
- For paternal grandmother, the mourning period is not 1 year for grandchildren.
- Usually, it is 13/16 days for general theetu (depending on family practice), and for some families, monthly Shrardham may be observed by the sons.
- For you, as the granddaughter-in-law, it is even more diluted.
So,
you can start your poojas again after the 13th or 16th day karyam is completed. This is the
widely accepted and shastric-based view for your generation level.
No need to wait 6 months or 1 year, especially for your own
daily Ambal pujai or Kalsam. Those who say 6 months may be applying some
potta-shastram or applying rules meant for immediate sons/daughters. It is not required in your case.
3. About keeping Kalsam during Aadi:
You can
safely keep Kalsam and do Aadi vellikizhamai or other Devi pooja. Ambal is a
Mother, and she does not see such theetu as impurity for those not in direct varisai. Your
bhakti and intention matter more.
A small note:
If your in-laws are very strict or still in grief, just check with them
not for permission, but to maintain peace. Some families have emotional connections with customs even if not scriptural.
But from a Shastric point of view:

You can resume Nitya pooja after karyam

You can keep Aadi Kalsam

No need to wait 6 months or 1 year in your role