Everyone has an accent. What you grew up with may sound normal to you, but it is not unaccented. There is no unaccented
speech, there are only different ways of speaking.
It's hard to know this at a gut level until you have spent several months outside your home country/state/area. The way that you speak will begin to adapt. This is called accommodation. However unless you start when you are under 10 years old it is unlikely to be perfect, and you will always sound like a foreigner.
On returning home, your acclimatised ears will hear the familiar tones in a different way, and realise just how strong the local accent it is.
This happened to me in 1993 whilst waiting in Lisbon airport, en route between London and Cape Town. Over the previous year, my pronounciation of the English language had become ever more London-influenced. I'd even started dropping or softening my 'h's.
Other passengers for the same flight accumulated. As the destination was Cape Town, many of them were South African. As they discussed rugby scores, I realised just how broad the various South African accents can be.