#1: it's absolutely normal to have "cold feet" and second thoughts as you come closer to surgery. I know I did. Heck, I was crying as they strapped me to the surgery table!
#2: Sagging skin is kind of a case-by-case situation with many factors contributing such as age, sex, skin type, general health, size/how much weight you have to lose, and possibly how long you've been overweight/obese.
I've been down the weight loss surgery path twice and my personal experience may help.
I had lap band surgery in 2005. I was 35 years old and had 125lbs to lose to get to "ideal" or normal BMI. I lost 90lbs of that. I made it out of the "obese" BMI into "overweight". I felt great and had VERY LITTLE sagging skin.
I had my lap band out in 2009 due to a slip and did well maintaining until 2014. I had some major upheavals in my life and did some comfort and binge eating. By 2016, I had gained ALL of my weight back and was right back where I started before the lap band. I had trouble sticking to diets and knew that my lap band had been successful until the slip, so I decided on the gastric sleeve. To date, I've lost 86 lbs and am about 15 lbs away from my all-time low with the lap band. I'm happy. I feel great. BUT...I'm also almost 15 years older and my skin (a source of pride and joy to me all my life) is letting me down. I joked to my family a week or 2 ago: I'm starting to look like a hairless Shar-pei dog. My neck waddle is OK in some positions, but if gravity is working against me it's downright embarrassing. My arms have developed flappy wings and my thighs look deflated with lumpy protrusions where my chub used to rub.
I'm VERY happy with my weight loss results and I wouldn't change a thing, but for the 1st time in my life plastic surgery seems like a real possibility for me. I started this 2nd weight loss journey with no plans for plastic surgery, even though a friend of mine (also a WLS patient) gave me her plastic surgeon's personal contact info.
My advice: you're young (22), decide what's important to you. You came to this WLS party with a dream or a goal in mind. Don't lose sight of that. Whether or not you get saggy skin, there are options. Best of luck!