Hey Troy,
Just text her "Merry Christmas

" and gauge her response:
IF she doesn't reply: move on, she's no longer interested
IF she replies with : you too, thanks, u 2, or any of those she's more than likely just being polite
IF she replies with: Same to you

, Merry Christmas to you too

or any thing showing your same level of input you got a shot
*Here you can possibly ask how shes been and gauge her response
*You want to ask her hang out in person to build up sexual tension
*Make a move and you're good
The hardest parts: Getting a response from her
*Girls move on a lot faster initially than guys do
*Girls retained their options, while men lose theirs when going into the relationships
*She could have a different guy on the scene
*You would of had to of had a strong sexual relationship with her!
*If she does come back she'll be looking for sex and if she doesn't get it she'll be gone
Questions, comments, concerns
Just Dave