Does Irelia Fervent's ability trigger when an enemy spell targets her?

Ruling: No, Irelia Fervent's ability does not trigger from enemy spells or effects. "You" refers to the controller of the card, so only effects controlled by Irelia's owner will trigger her ability.

Nuances:

• An enemy Stupify targeting Irelia would result in -1 ATK (no trigger from her ability)
• Enemy effects that choose or ready Irelia do not trigger her ability