Good job for a first timer. As mentioned above, the box type is incorrect. Otherwise, it is not a tough patch at all. May want to consider texturing that entire wall so that it's look good and be extra careful with the dry wall screws.
As stated above. There will be multi voltage taps. One should be labeled "Com" / "Common. The com goes to your neutral lead, then your hot goes to the appropiate wire on the ballast labeled "120v".
These lights take a few minute to reach full brightness. If you quickly turn them off then on...