Replying to First Backflip Without Preparation?

So I know that there are a shit ton of threads on backflips but I want one for my situation. I really want to try a backflip for the first time this week but I have no way of prepping for it. I'm decent at them on the trampoline but it's been a while and I don't have a soft jump to try it on so I have to take it right to the park. Should I just man up and throw it or am I gonna get myself killed?

Also is there any way to be a little less afraid of it? I was gonna do it today but my knees were literally trembling because I was so scared and my heart was racing lol.

Oh yeah and the jump I wanna try it on is decent sized but not poppy if that means anything. I'm pretty comfortable spinning and grabbing off it.