just needing reassurance

Brittanie • Ariel Diana Nichole was born 9/7/16😊 Pregnant with my 2nd 💕
My daughter is going to be 3 months old on the 7th of December. This Monday (the 28th) we have an appointment at Vanderbilt Hospital to get some x-rays and to see a specialist due to her head being an odd shape. It wasn't like this when she was born. The top of her head is slanted, her forehead comes out a little further on one side, same as the back of her head. 
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Mind you, she learns great. She hold her head up semi-well during tummy time, she sees people from a distance and smiles at them, I've gotten her to laugh, she reaches for toys on her play mat, etc... so I don't believe it's keeping her from doing anything. I'm just a very nervous FTM because I've lost a lot of people due to complications in the brain, this happening to her (big or small) is making me a nervous wreck.
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How common is this? Has anyone else dealt with this with their baby before? I just need some reassurance, encouragement, or positive words. Thanks ladies...