Which language should I learn first?

My main language is English, but the funny thing is that both my parents are from haiti(a creole speaking country,but the official language is French)and I can barely speak creole.I want to learn how to speak creole fluently so I can spread the gospel In haiti.But I heard that most pastors in haiti speak french while preaching and they also use the french bible,so should I learn to read creole and speak it fluently or should french first.