She was ok with the mc making that choice:
Jill: "Oh... Yeah, of course. I understand."
Jill: "I didn't plan anything big. It was spontaneous."
Jill: "You're allowed to have other plans. Haha..."
Jill: "So, uh. Happy birthday."
mc "Thanks, Jill. I appreciate it."
Jill: "(I can't blurt it out now... Crap...)"
Jill: "(Maybe it's a sign?)"
Jill: "(Maybe it's best to not even tell him...)"
But at the same time even if she understood his motives (she wasn't jealous in this case), it changed the course of events.
The fact that you get severely penalised making a chick decision when dealing with a chick oriented girl, seems to be the thing that bothers people the most. But to me, just choose Jill if you want Jill. Choose Sage if you want Sage.