Factors that make Qurbaani waajib

Qurbaani for an unmarried girl

Q: I am a 25 year old unmarried woman (will get married in a few months). My parents passed away a few years ago and I don't have any other siblings. I live with a relative in very good condition. I am presently working with a medium level salary and I have a little inherited gold and a savings as well.

Please tell me if Qurbani is fardh on me? Some people say it's not because I'm an unmarried orphan, some say it is because I'm independent and earning myself.

Performing one qurbaani for the whole family

Q:

1. Is one qurbani valid for whole family living under one roof?

2. I have heard that qurbani is wajib but I have seen many aalim's videos who say qurbani is Sunnat-e-Ebrahimi. So if a person does not do it, its not a sin as its a sunnah act, is it true?

3. I do not earn and I am dependent on my father but I did have some savings, was qurbani wajib on me though I gave that money to my mother 3 days before eid as I feared sin.