That kid is 12? Your timing is good, but there are some technical things you could work out. First off you could get a little lower which would make him look higher up.
If you have the trigger and receiver and flash then you can just lay the flash on its side and it will work. Hell have someone hold it for you. A gorilla pod is cheap and you can get it at walmart. Rig up anything because it is worth it.
The PP is not great. The white balance is different in all three. Were you using a manual white balance or did you change it in PP? The first two are underexposed. All three look like they could use some contrast adjustment.
The third one is definitely the best exposure, timing, and position of subject, but I liked the camera position in the other two more.