At higher levels in League of Legends, your IP and XP earned from AI games gets penalized. Does this impact the "First Win of the Day" bonus though? Some days I just want to mindlessly blast through a game and get the +150.
No, the +150 bonus-of-the-day is not impacted by playing an AI game or a Custom Game instead of a PvP game. You need only make sure that you win the game, and you'll earn an un-changed +150 IP on top of however much (reduced) XP/IP you get normally.
It's actually not uncommon that some players will specifically do a relatively quick AI match just to secure that win, especially if you're having a bad day on the PvP end.