Up. That has been the main direction of Twilight's life. At first, she got a pair of wings allowing her to fly through the sky. Then, she was given a crystal castle overlooking the entire village of Ponyville. However, Twilight found herself strangled with her new gifts rather than feeling happy; for every step higher came at a loss of something important and precious. Like usually happens, the understanding comes too late.
Sequel to "Why me?", in some sense.
While I do have to wonder how Twilight must have felt not having a choice in the matter of her ascension, she seems kinda selfish for not considering the fact that Celestia and Luna might feel the same way. On that note: it also seems that Luna might have had some more reassuring words for her (although to be fair, that sort of thing might be more Celestia's particular forte)