Meppen-Walter, 18, admitted the crime after his arrest for the crash on September 1, which killed brother and sister Kulwant Singh and Ravel Kaur.
Ms Kaur's two teenage sons were also injured in the accident, which happened when Meppen-Walter's grandfather's Mercedes C220 hit a Nissan Micra as it emerged from a side street in Manchester.
The 16 and 17-year-old boys have been left orphaned by the accident, with their father reportedly killed in their homeland of Afghanistan, which led them to flee to Britain in 2001.
It was revealed that Meppen-Walter - who wept throughout proceedings - was speeding at 56mph in a 30mph zone, and that he had one previous conviction for driving at the same speed in a similar area.
In the aftermath of the accident he tried to help the victims, and was overheard crying "what have I done?". He is expected to be released after eight months although could be let out earlier with an electronic tag.
The former England U17 international was also banned from driving for three years. He has not made a senior appearance for City.