Am In trouble at work?

I started two months ago in fire systems as a helper, I like it a lot and done two jobs already, I was sent to a freezer in a warehouse recently and everything is fine except now we are dropping wire, from 30ft up and we have to step out of the lift on some narrow rails with no harness. I can do 2 or 3 but I'm scared I could slip. Now I get called girl and I see the other guys do it like nothing, I told supervisor I'm not embarrassed I am scared. I just drive the lift right now. I was doing good and learning and working hard, but I can leave the lift to drop wire. I worried ill get fired, when they're done with that I can go back to work with the rest, that is just too high and slippery in the ice for me.