Many of my friends (both believers and non believers) asked me why there are so many versions of english Bible and which was the correct version to read. I can easily relate to this because I myself was on the same boat at one point.
Anyways, for those who have the same questions and concerns about these multiple english versions, I think the question should be what is the difference rather than what is the correct version.
Here is a very well put together diagram by Dr. Walt Russel that shows the translation spectrum of different versions of the English Bible. I found this to be very helpful and I hope it will be for you too. I personally think reading both KJV and NIV version in parallel gives a better understanding of the scriptures.
Hey, if you can learn Hebrew and Greek that is even better for studying the Bible 🙂