Sometimes the name they chose is from a favorite television show or movie character. On occasion it is that of their best friend or an idolized family member. I went through this stage for an exceptionally long period of time (there is some debate as to whether I am out of it yet - and I probably would be if I could ever conclusively decide on something else) and most of my choices came from favored books.
Sophie has now entered this stage. She started off by being rather inconsistent as to what name she wanted to be called each day. On extreme days it could even vary by the hour. One of the best parts of this game is that she refuses to tell you straight off what to call her. Instead she makes you guess, and doesn't respond or acknowledge your presence until you hit the right one. There is quite the lengthy list to choose from, and considering that she often requires combinations such as "Princess Ladybug" or "Her royal queen Sophie Christine" this can be very time consuming. I swear she didn't answer me the other day until I called her "Your royal highness grand supreme dictator of the ultimate and unlimited dominion."
The name she seems to have stabilized on the most consistently though as of late is, ironically enough "Abby." I could blame the adorable pink muppet with magical powers, or the fact that she spends enough time at the doctor's office that they could add a new wing through her bills, and all "official" forms have her as "Abigail." I could blame my six year old, who has never fully accepted calling her Sophie. But I can't blame Chris, who out of respect for me, or perhaps fear of the now perfected glare of doom, refers to her only as "Ladybug."
She insists that her name is Sophie Abigail, and that we must call her "Abby." To her father, she recently retorted that she was not a bug, and not to call her one. Surprisingly, I am okay with this recent development. More so than I thought I would be. It could be because Abigail is actually a rather pretty name, just not the name I wanted. Or it could be that Sophie is a force of nature not to reckoned with, and far more stubborn than I am.
I have thought about dropping her middle name, and just having her be Abigail Sophia Stewart, but that leads to rather unfortunate initials. It seems hyphenating it may be my best option at this point - Abigail-Sophia Christine Stewart. Quite a mouthful really, but a name that befits a royal princess - which she believes she is. I tried "Sophiegail" but that was quickly squashed.
Amazingly enough this sort of disorderly conduct when it comes to names is fairly common. My home teacher, when I was relaying this ordeal, said that his brother went through something similar. His mom always called him by the first name, and the dad called him by the middle name - and now his brother switches between the names dependent on the situation (one is more professional sounding than the other)
I, out of habit, still refer to her as Sophie despite her requests. Which could be why she did not stop coloring on her brother when I politely asked "Sophie" to stop, why she continued to play with her brother's GI Joe that she commandeered to go with her Barbies at bedtime, and why she continued to drive his toy truck filled with LGM's despite his pleas and my insistence that she let him play with his toys. That, or it could be an inherent natural desire to torture her younger sibling merely because he is last in line in the birth order.
Reasoning not withstanding, basically feel free to call her whatever you choose. When she is old enough, she will probably choose something entirely different from what any of us call her anyway, merely because she can.