Pencil Sketch - My Lovely Duo

Following the Pen Challenge, I was pretty inspired and did a sketch using pencil (without erasing). After much thoughts, I picked a photo of the children at the Go-Kart during our recent trip to Johor Bahru. It was our virgin ride on a race track and definitely a memorable one.  

Took me an hour to complete the sketch as I am not familiar with drawing human features. It is hard to get the proportions right and even more challenging to work on the details of the eyes, nose and mouth.

The kids thought it did not look like them but I thought it was a pretty good effort. What do you think?