“Do not mind the ugly picture, I just had to sketch something quick so I can write all this :XD: I just wanted to share what I thought of Celestia and Luna, I do not consider the comics canon (they mess up a lot of things :x) so whatever happens in those does not affect what I think!
 
I like to think that Celestia and Luna were born or ‘created’ as they are in this picture - not in their cutesy-wutesy daww adowable filly versions that a lot of people like. They were created along with the first rising of the sun and moon - and because the sun rose first that makes Celestia technically older than Luna, even by just a few hours. Uhh they weren’t sure what their purpose on the Earth was so _{~all events of Hearth’s Warming Eve here}~ and then they realised that they were made to raise the sun & moon and they did that and stuff  
Celestia & Luna were of the same stature and build, but then Luna put some of her power into Nightmare Moon so she became smaller, how she is now in the show ; This is also where the black spot on her flank came from, a permanent reminder of Nightmare Moon. And why I sometimes draw Luna with only the moon symbol on her cutie mark, w/o the black spot
 
Okay after that mess ( I am not very good at putting my thoughts into words ) here are their personalities that often impact how I draw them ^.
 
Celestia: As bright, and vibrant as the sun, she brings life wherever she goes. Very friendly and sociable, she loves to laugh and make other ponies happy ; has a great skill in cheering people up. But do not underestimate this happy-go-lucky princes, she can be serious when the time comes!
 
Luna: As dark and mysterious as the night, but as elegant and serene as the moon. She may come off as cold and apathetic (well, she is) at first, but it is only because she does not want to get close to anyone in fear of hurting or being hurt. When she loves you must savour it, you can trust that it is true and everlasting.”