I have just switched from American Style to International too!! I also completed the entire bronze syllabus in American style rhythm prior to switching.

I have had 3 or 4 classes and am still finding the very basic elements of rumba challenging to learn but I love it!! I think the foot and hip techniques produce a beautiful look even if they are sometimes painful to execute.

Because my teacher was very strict regarding technique in American style, it is not as difficult as if I was starting without any previous ballroom experience, but I think you will find that you move much more slowly through the syllabus. Also, I am told that having a strong foundation in rumba will be very helpful will all the other Latin dances so do practice those rumba walks!!!!

Good luck to you!