Writers? Do you feel pressure when trying out a new genre?

I'm writing my first science fiction story as well. Pressure isn't the word for me. I feel a little overwhelmed, but not forced or pressured. I overcome it by researching and learning as much as I ca, everyone starts somewhere. I would encourage you to read science fiction though, it's a good genre and reading the genre you're writing is one of the best ways to become accustomed to it.