Hey Ivonnely,
First things first - flying is very safe. The pilots don't want to die either! My boyfriend hates flying and he likes to read technical/physics explanations of flight mechanics as well as safety statistics and explanations for phenomena like turbulence, engine failure etc. It's sort of like going to the doctor for a scary medical procedure and having the doctor walk you through each step, explaining what he/she's doing all along. It also helps to watch other passengers. Look at the people who "know what they're doing" - they are just sitting there reading the paper or whatever like it's no big deal.
Secondly - if turbulence/sensation bothers you, I recommend taking Dramamine. It dulls the inner ear sensitivity to prevent motion sickness, but it also means you can't feel all the subtle little balance changes when the plane is turning. Just take one pill (it says take 1-2) because 2 will make you stoned and sluggish.
Third - If you have stressful connections or miss your flight or there are delays or cancellations, you'll be surrounded by other people in the same boat. You are going to live with your fiance, so even if it takes forever to get you there, you will make it. Make a point to be polite and calm when dealing with customer service reps.
...Besides, you're so darn cute I bet you'll get a free upgrade or priority standby.
I understand about being nervous. I regularly fly by myself between Asia, Europe and the USA and I still have moments of "crap, what if the plane just crashed now?" But so far none of them have -and the chances of being on an actual doomed plane are slim to none.