She acknowledges her mistake several times in the long interview video. Should she be making like Opus Dei and be scourging herself while she says it so you might believe her?
Punishment is supposed to serve multiple roles of punishment, denunciation, and both specific and general deterrence.
She has been roundly denounced. Her life has effectively been put in shambles for the last 4 years while the matter worked its way through the courts. Her life will continue to be severely affected and limited by her notoriety as a stupid person and by now having a criminal record. On top of that punishment comes a 90-day jail term, a multi-year license suspension, and the equivalent of 6 full work-weeks of community service .
How much more would you pile on to a young person with no prior criminal record and a clean driving record up to that point, for an act that while stupid was at least motivated out of well-meaning and not reckless adventure.
That was punishment. Some will say that 2 people died and you can't punish her enough for that. Those people will not be satisfied no matter what she gets. The thing I would be more interested in when determining the length of a driving ban is is, is she likely to do the same thing again? I don't think she would. If so, a lifetime driving ban is pointless and provides no protective effect for society.