There's a sort of sliding scale to missions. When you get into your first good frigate fit, you'll kill the enemies in 1-3 hits and your only real concern is being swarmed because you don't have the defense (shields or armor repair) to survive much incoming. That lasts through your destroyers. When you hit cruisers, things get a lot better as your tank goes WAY up, though your DPS doesn't improve a whole bunch due to low skills. You'll feel like you become more and more powerful doing level 1s and 2s in your cruiser as everything you face is usually frigates or destroyers. Once you have enough faction to do level 3s, you start running into swarms of cruisers, which will again gang up on you and exceed your tanking ability until you get into your battlecruiser, when you'll again feel like a god among mortals. That lasts until you do your first Extravaganza L3 mission, where you'll get jumped by like 20-30 ships. Your skills will continue to improve in tanking to the point where you don't really worry about dying any more -- just waiting for your 5.0 faction to start level 4s. At this point you'll have some T2 gear and probably training for those week-long skills for T2 weapons.

That's been my experience, anyway.