Yeah, it IS a big deal, definitely. I was very scared too. Petrified. The closer I got to surgery day- the more scared I was.
In my case, although I was scared, I kept going through the process of getting my surgery, kept reading up on the surgery, kept reading about post-op issues (good and bad) and generally tried to educate myself as much as possible. While I was doing all this, I was also keeping in mind that until I was on the table I could still back out.
I went through with it because my quality of life and health as a morbidly obese person were quickly diminishing. I have a very strong family history of heart disease and at 38 I was diabetic (II), had high blood pressure, high cholesterol, sleep apnea, arthritis, zero energy and was clearly headed for a heart attack in another year or two. My father had his first of 6 open heart surgeries at age 40 and died at age 59. The gastric bypass seemed much better to me than my Dad's 6 heart bypass surgeries and 19 years of dying.
Ultimately, no one (but your doctors) can really give you good advice on whether or not to do it.
Personally, i'm glad that I did it and I've never regretted it. I'd do it again in an instant. Oh and BTW... My insurance didn't cover mine. I paid out of pocket and I am NOT a wealthy person. I really felt that, in my case, it was, "if you want to live and be 'ok'- this may be your only shot. If you don't do this, you'll keep the weight, the illnesses will get worse and you can die like dad did."
I could still die like my dad did. Genetics don't always play fair, but my quality of life is soooo much better than it was 15 months ago. It's like night and day.
Best of luck to you. Do what's best for you- whatever that may be. Be strong!