Say I completed my chores, im 13 btw, then I see like some other type of chores that is not done. Then say I dont help finish those chores, would it be a mortal sin
I don’t think it would be a sin because you finished your assigned chores. But it would have been a big help to do those unfinished chores. If you were having problems getting your chores done, wouldn’t you appreciate if someone helped you?
It wouldn't be a mortal sin regardless. Its not a serious matter unless your chores involve feeding starving orphans or something! Do you have a catechism? Look up what serious matter means. Or google it even, but be careful what site you trust on the net!
Whether it is good or not to also do those other chores also depends on a lot of things.
1. are you a person who usually helps a lot and tends to run himself down trying to do everything and obsess TOO MUCH about unfinished things? Then I would say learn to leave htings be (I have had to learn this.,... still don't always succeed); or are oyu a person who always only does the minimum but would have a lot of energy left to do another chore - then I would say, think about it ;)
**2. **How important is trhe chore, is it something that can wait,have your parents specifically asked you to do this, would it make somebody very very happy, or is it something that doesn't matter if it is done at another time?
**3. **How do you feel, are you already tired, have your othet chorse taken a long time?