You'll probably finish at level 45 or so, if you go straight through the questline and skip all the side quests.
A word of warning: Grizzleheim and Wintertusk are two side worlds that lead to many utility spells and your school pets. If you skip these "optional quests," you will be unable to earn utility spells for level 35, 55, 72, 75, etc. You also will not be able to earn any school pets past level 48.
If that's the case then I agree and there, I corrected your little typo for you :P
Now to the subject at hand. Since you intend to skip sides, then you'll end up being at about 45-46; considerably low for Celestia in my opinion.
You need to understand that limited help is available nowadays, so you may end up soloing most of these words, don't hinder yourself from now because your level is too low to complete certain quest(s) making you "stuck."
Don't ignore Zeke's Quests or Grizzleheim and Wintertusk either! You will need the spells only accessible here and the training points offered by Zeke!