Marriage is a hard work and a full commitment. Even more so is an international and intercultural marriage that involves moving countries and continents. Both spouses are a team and they must absolutely trust one another.
From my own experience, no matter how challenging the long distance relationship may seem, your wife's integration in America phase will be much tougher. If you have doubts now, the situation may become even worse afterwards. Sometimes one should have a courage and cut the losses early.