You'll find Celestia is much easier after level 48, when you get your scarecrow spell. To answer whether you are "too low" or not, are you struggling? If you are having a rough time in Celestia then yes, you're too low. Are you doing fine in Celestia? Then your level is fine.
Unless you are a very experienced player, I would advise against attempting Wintertusk below level 50. It is a much more challenging world than Celestia is. Worse, you will not be able to block critical hits because gear under level 50 doesn't provide critical or block stats. The mobs and bosses in Wintertusk love their criticals....
, is that too low?
Alia Misthaven