There's a small chance it's possible to survive. It is heavily and repeatedly debated here.
My suggestion would be to do what athletes do and repeatedly visualize, use the senses. Imagine every step. Surroundings. Sounds. Sensations. Etc. Imagine succeeding. Imagine failing. Imagine surviving. Imagine the fall and how you want to land. Feel the feelings of when you abandoned the attempt. Imagine overcoming them. Imagine the moment of impact. Imagine your body being taken away after success.
You'll know when you reach confidence. I don't think you'll still have the pressure of "needing" to ctb. If it feels like the right decision, you'll be able to do it.
