Princess Twilight Sparkle, Princess of Friendship

The last of the princesses (if you count those with a real title.. Since Princess Flurry Heart is only a filly) I called all the others 'mother of' but not this one because... Twilight seems like only a teenager or so to me, so to me, too young to be a 'mother' of anything.. Now I don't know how the aging going in MLP but, this is kinda why I didn't call her the 'Mother of Friendship'