Cleric, Pegasus Knight, and Knight are pretty good base classes.
Her mods are: -2 Str (this is where it hurts b/c she would seem better as a Physical class but can do ok with special classes as well) +2 Skl +3 Spd -2 Def (hurts as well but she does get Pavise +1 Res
Doesnt seem that bad at all in my opinion. Luna really buffs her Damage output.
Because her only competition, in terms of Pegasus Knights, in this game is Cordelia, who is the 3rd best 1st Gen character (below Chrom and the Avatar), and her daughter, who can be better depending on the father.