Ok, at first, even on MASTER difficulty, I was under the impression this game would be quite easy to beat. Everything from bandits to wolves etc seemed easy to kill with a few sword strokes, despite doing some decent damage in return, however. Anyway, I spent quite some time chopping wood and buying every iron ignot the guy in Riverwood was selling. After a bit of time and fighting everything in the surrounding areas, without deviating too far, I levelled my smithing up massively, which in return levelled me up too. Now, at level 19, I figured it was time to get on with the game and venture much further. Having killed some bandits near the mountains just up from Riverwood back when I was around level 10, I was popping upto the mountains again, now at level 19, and I stumble upon a Frost Troll. Ok, pulls out my Exquisite AXE and approaches him, after using all my magic first in a fire attack on him. I start laying into him and I notice his health has barely moved even 1/20th and he whacks me on the head, killing me instantly. Tell me, have I screwed myself starting the game at this level, because I imagine there are things much stronger than this! I'm now very scared!
What would happen if one started from the max character level before venturing, levelling using smithing and spells etc. It would be crazy!
Except for the dragons you fight, it's a lot more about which areas you are visiting than your character level.
Each area has some range, like level 1 - 5, 5 -10, 40-50, etc., and when you enter, the area gets locked to whatever level you are, or the lowest or highest end of that range (if the PC is lower or higher level). The areas closest to Riverwood and Whiterun are mostly lower level, and most of the higher level areas are high up in the mountains or remote locations.
I'm at level 33 on master now and I find some areas that are much lower level and other areas that are still higher level.
As for the dragons, they are treated like an area unto themselves, so they will scale a bit more to match your level.