A couple of thoughts for you Sharon.
1. This is classic street photography. A lot of street photographers work almost exclusively in B&W in order to try to simplify a busy scene. This is very definitely a busy scene. Removing all the colour from a scene is a very powerful way of simplifying something.
2. Photography is all about the light and the light here is harsh and unattractive. The dappled light that the branches of the trees cast is something all portrait photographers are taught to avoid at all costs. Here, as Donald has pointed out the lack of tonal variation is the enemy of B&W work and in this image there is very little tonal variation from the blacks right through to the 3/4 tones, so not a great candidate for B&W (the histogram shows this quite clearly).
As others have pointed out, you might get a better result by leaving this in colour. Having all the colour data thrown out might have been the wrong direction as if everyone is wearing different coloured clothing you might just get some of the separation that this image needs (if they are all wearing similar coloured clothes, this might not work either).
Finally, simplify this composition. Others have suggested that the buildings and trees can be cropped. I would also remove the people on the right hand side. The power of this image is the person on the left looking at the three protesters facing her.
Also, one other consideration is to set this image aside and return to it when you have the skills needed to make the changes you are looking for. I finally figured out what I needed to do to a particular image I had taken 8 or 9 years ago and when I worked on it earlier on this year it went from a so-so image to an outstanding one with about 20 minutes worth of work.