No it's not selfish, especially when parents etc are all still young and active.
The only thing I would say though is, if you have a close relationship with your parents, you might want to think long term wrt aging, declining health etc, and whether you could envisage your parents becoming older, and potentially dying without you being there.
It's a long-term prospect but is one which ime many people don't think about when they head towards living in another country.
Living in a different part of the country is not the same as living in New Zealand where it's not possible to pop over for a weekend or a hospital appointment or be there towards the end of life.
I grew up in South Africa and we returned to the UK in 1993. When we first came home my grandparents were in good health, but they both deteriorated within coming years and they died two and eight years after we came home respectively. My mum was very much involved in their care, not as a carer but in being part of it, with their medical appointments, communicating with doctors etc esp for my grandad who had multiple health issues towards the end.
We didn't come home because of the prospect of grandparents becoming older and potential for illness/death, but I do think that if we'd still been abroad when my grandad's health had started to deteriorate my mum would have found it difficult not to be there, but it's very difficult to decide to move back because of ailing health of parents, and to have regrets if you are not able to be there towards the end of life.