I am the first grad student of an assistant professor (chemistry/biology). Seeing her writing workload has made me a lot less enthusiastic about being a professor myself. I like writing about science, but the constant treading water mentality makes it difficult to 1) find the mental space to be creative and 2) take the risks that are often necessary for innovation, especially since the careers of your trainees are on the line. The kicker is that most grant writing isn't even about science. Good luck with your lab!