Charcoal portrait

On the weekend I bought the magazine "International Artist", what a fantastic magazine and so full of inspiration!  I was particularly inspired by the charcoal portraits of Ellen Milinch.  It got me thinking that this is something I would really love to do too.  Children and babies are of particular interest to me.  So I decided to give it a go myself, I drew a charcoal portrait of my eldest son Thomas when he was 2 years old and this is the result (click on the picture to see a larger version).  I think the paper I chose let me down a bit (just ordinary cartridge paper), so next time I will be using proper charcoal paper and try and render a bit more smoothly.  Otherwise I'm quite happy with it and I think I have captured his essence and expression.  I would actually love to attempt to paint this picture.  I have a canvas that would be the perfect size.  Acrylics or Oils?  I have no idea.  I only have a tiny bit of experience with acrylic and have never used oil paints before.