Do the event.
You end up with more overall SQ and a very good AE Welfare servant.
If ever there was an extra class servant you want as a new player it is an Alter-Ego. She can fill in any gaps you might have in your team for lack of an ST dps Caster, Rider, AND Assassin!
Good ST casters* and assassins, in particular, when you first start out, are almost non-existent and by virtue of being a welfare (Free np5) she will actually do more damage than her 4 star and some 5 star competition.
This is NOT a welfare new players should skip!
*That said caster Shuten is the welfare servant for the very next event so do it for lack of good st assassins