Sort vertices coordinates

I made a petal shape from 5 cylinders, deleted unwanted faces, merged vertices and added new top and bottom faces. When I exported with three.js, my top vertices coordinates path is like in the image below. If I export a not joined mesh, like cylinder, vertices coordinates path is beautifully round, not going from one side to another. Is it possible to do the same with joined mesh? How can I change vertices order to be clockwise or anticlockwise?