My 16 yr old niece had severe scoliosis and rotation that was progressing quite quickly. So they did a 9 level fusion, I believe it was, with hardware. She seems to be doing fine now, her surgery was just last summer.

I do suggest getting second or third opinions and going with the best surgeon you can find.

You can always postpone the surgery if you aren't comfortable with the decision yet.
If you decide to do that, it's best to let them know as soon as possible so they can change the scheduling at the hospital and for the Dr.