Light is a smaller version. It does not have everything that STD
has. Which is why the Desktop was not there.
No, the desktop was not there because X won't start. IIRC, all ways of installing Light result in at least a window manager, if not a desktop-like environment.
BUT it is true that STD is slightly more likely to go to X as intended, and will be easier to fix if it doesn't as more people are familiar with it so more help is available.
Light is a bad choice for a first Linux; STD is much better for that.