It was spoiled for me, by a friend who claimed "don't bother levelling up 'Aries' because she dies." This guy hadn't got that far himself yet, but had been told by another friend.
I took it onboard, but figured the game would give me the potential to affect the outcome in some way.
When the scene finally came, it wasn't a huge surprise but it still hit me really hard, emotionally. I was quite attached to her as a character, and I was heavily invested in the game as a whole. I was 16, and it was the first big plot-driven RPG I'd every played - it was hard not to feel for this fictional heroine whose story I had shared for well over 30 hours.