changing minhag?

I was raised secular and assumed that our family was Ashkenazi, but a few years ago my dad told me that our family is sephardi. (!)

Main question is; what issues for an observant person (I’m not there yet) would come with changing minhag?

Is it permissible for an ostensibly Ashkenazi Jew to begin holding by Sephardi minhag if there’s reason to believe it should be changed, or does it not really matter which minhag you take?

Thanks in advance and chag sameach!