Am I right to feel jealous?

You're certainly not wrong to feel jealous, it's a natural component of grieving, even all these years later. It can be frustrating to see people in a priveleged position, especially when they don't quite realise what it feels like to not have a constant like a close family member there, and whilst everyone copes differently I think everyone envies those who still have the family members and friends around that you've lost.

My advice is to recognise that you're not wrong, you're just grieving and that's perfectly natural. If you feel uncomfortable around the topic or feel you want further closure in terms of your bereavement - as this is a really significant thing and even bringing it up here is brave - I strongly advise you speak to your Dad about it and/or seek some form of support in the form of a friend or even counselling. It might feel strange doing it all these years later, but old wounds hurt the hardest and it's important you look after them, trust me.

I'm sure your Dad thinks about her just as much as you do, it probably just hurts him to focus on her. Look after yourself -- you're not alone.