This is Final Fantasy Tactics Advance.
I've never played it, but I just typed "you can't be the new kid forever" and found it. XD
Then I brought my husband over. He said he played it and it was great. He said it's really cute. The Final Fantasy Tactics games have a unique battle system. It's sort of grid based. You make a little army with different races and classes and then move them around the grid.
Here's some art of it You can see the red haired girl and the main character in the art.