My mother tongue is Afrikaans (a sister language of Dutch) but I'm fluent in English, in a lot of ways my English is better than my Afrikaans because all the media I consume is English and my job has mostly been in English.
I love my mother tongue and I'm more expressive etc in it, it's also allowed me to land a job that's in the Netherlands, because I could learn Dutch really quickly thanks to it.
Both languages have been so valuable to me, I hope to one day expose my kids to a few different languages from a young age