Please consider all options before you move forward. The issue is that since you have an interest only loan right now, your payments might not necessarily reduce. You would (unless you choose another interest only loan) now be paying principal as well as interest. Other reasons for you to consider would be getting into a 30 year fixed rate loan, reducing your mortgage insurance payment if you have one etc.
If you would like to work with a Mortgage Expert who will take the time and effort to evaluate your specific situation, please call me.
I wish you the very best, whichever way you decide to go.