If you didn't know that Aeris dies, sorry you read this thread.
After playing your first time through, does anyone play with Aeris other than when you have to? As for myself, after you are allowed to switch your party around after leaving Midgar, I put her in the "henhouse"(I usually use the guys in my party) and never pull her out. It seems like a waste to power her up only to have her die later when I can get Barret and Yuffie levels as they have stand-alone fights later in the game. So does anyone actually use her other than when you have to?