For a first Celine. I would pick a Mini! Such a versatile and classic Celine! You have to have it!
The Phantom have a very lovely and stylish look but it isn't as pratical and iconic as the Mini.
The color depend of what you have in your wardrobe. Midnight or sand you can't go wrong. These colors are both year round. For my personal taste I would pick up first the Sand Mini especially in drummed leather as it is low maintenance and such a classy neutral but a darker color is a great option too! Good luck!
I also vote for phantom in midnight phantom is big and bulky but in the natural calf leather it looks very pretty and with the phantom bag it makes a statement in the room I have the phantom in natural calf burgundy and I love it I don't use it as an everyday bag burcause of it's size and because of my collection but when I want to make a statement or bling up my outfit I would chose my phantom good luck and please tell us your choice