I guess my take would be to say each of us are different in so many ways this would be a difficult Q to answer tailored to yourself.

My thoughts...
If you are moving up and truly know when to depart back to a prior comfort zone then you may be doing the right thing. Certainly this would be more true if you are winning through skilled play and not whimsical or lucky attempts at capturing the pot. Do a true (honest) analysis of your game.

It has become apparent to me that in poker you can be ever so close to playing a superior game but still ever so far from that game. There is no doubt in my mind that to really play well you have to not only be knowledgeable and patient but you also must have the ability to (really) capture information on how those around you play. This is not just how passive or agressive someone is but consists of many many things to be watchful of and learned for later use. You certainly seem to allready know this.

The comfort factor, learning from my own experience, comes from being placed in an uncomfortable situation and realizing that you can handle and master it. This I believe this is true of life in general and not just poker. Like playing poker, in life you can be close to acheiving comfort but still far far away.

Most of the real winners, in life, get there out of reasoned determination to have success. They take on reasoned risk which weigh in their long term favor. They know as only you will know when to face the fear and persue the comfort.

If the risk are well reasoned then I think you should persue it! I have learned that fear of failure can also be a positive motivation to succede. It really depends on how you honestly look at it and move correctly to change it.

Monty