Helena was shocked by Ivy's excitement but kept a cool exterior.  She had seen weirder, but she wasn't sure how much she could handle the excitement.  Helena was overall a calm person so mixing with Ivy every day wouldn't be the easiest, but she would try her best.  "Oh, we'll if your brother says you shouldn't then maybe you should just ask me," Helena said with a friendly smile.  The school was about controlling powers which included controlling yourself.  Helena figured Ivy would learn to control her excitement eventually.