I agree with every poster here and wanted to chime in because you sound as terrified as I was. It took me YEARS to work up to it - I waited HOURS in line when it first opened, and walked out!! - but it was really fun. I do agree the backwards part did not feel upside down, which I've done before, but more like disorienting and a tiny bit of those stomach drop feelings. I never felt unsafe or upside down, just...confused haha! Actually, I disliked the backwards part the worst, the big drop you can see I didn't even feel! Please don't let that scared you off, it's over very quick! Beware there are some bunny hills after the big drop but they too are over fast. I would say give it a shot if you can, I am happy I did! If you end up not riding, don't beat yourself up. We all have stuff that makes us scared and it's ok to not do it.
A tip I learned: if you hate the stomach drop feeling (and can prepare for the drop somehow), clench your stomach muscles and push your feet flat into the ride vehicle floor. I do it a LOT and I can say I truly feel a difference! If you do ride and hate it, at least you know and you don't ever have to do it again!