I went into my initial consultation thinking that I wanted the sleeve, but my surgeon pushed me to get gastric bypass instead because I had a very high starting BMI (over 60). I had gotten the impression that the sleeve was a more modern, less risky, less extreme surgery, but my surgeon explained that the risks are about equal (although there are different risks), and gastric bypass typically results in more weight loss. I was unsure at the time, but as I learned more about both surgeries, I became more confident that gastric bypass was the right surgery. It might just be confirmation bias, but I've seen a lot of people talk about getting severe GERD with the sleeve, and/or not losing enough weight, and getting a revision to bypass.
What surgery you get is YOUR decision, though, so if you are not comfortable with it, you have the right to cancel. However, it's best to avoid making big decisions when you're in a heightened emotional state, so what were your thoughts a few weeks ago when the surgery was a little farther in the distance and you were in a calmer state of mind?