I would certainly contact her but keep in mind she has her own idea of how things went between you and what sort of person she would like to be with, etc. In other words, you won't be picking up where you left off, start as if it were a wholly new relationship -- after two years, it is, you have both changed and you only have your own idea of what she is like to go from, which might have nothing to do with who she actually is. Remember that and don't let it get in the way; stay in the here-and-now or you could hurt yourself.