It's 50 scrap to upgrade the cloak to max. That's 2-5 jumps, depending on difficulty. Sure, you might run into some rough enemies before that happens, but nothing in the first sector should have the firepower to take you out in the Stealth B before you either kill it or escape, so long as you're managing your crew efficiently.
My last Hard run with the Stealth C left me with 2 hull after the first jump (enemy ship had a minibeam, beam drone, and... something else, I forgot, but it hit my drone room right off the bat), and I still made it to the end of Sector 3 - a bad start is understandable, but most of the time it's not the bad start that kills people, it's giving up.
But the stealth C doesn't have shields OR a cloak, nor does it have particularly good weaponry, so it's a lot more difficult than the stealth B. I honestly can't see having much of a bad start with the Stealth B. I mean, it's possible, I'm sure, but it's just... not super likely.
Also, don't wait for the enemy to fire and then cloak until you get more engines. While it's a nice trick, the max cloak gives you more than enough time to fire before they fire their weapons, which is far preferable. You've got the Long Range scanners, so you can avoid environmental hazards pretty easily - actually, I can see the map screwing you over once in a while, I had one that forced me through two asteroid sectors a couple months ago (only path to end beacon), before AE came out, and I think that may have managed to kill me when the second one had beams.