Should I take the leap?

My dad used to read to me before bed every night. I was obsessed with books as a child. As I grew older, I started writing. One thing led to another and, by the end of high school, I had studied dozens of movies and written dozens of screenplays.
Now, I am at a crossroads.
I have the option of pursuing a career in health sciences. In terms of employment, it is the safest way to go. On the other hand, I love writing, and I want to be a screenwriter (or at least work alongside screenwriters) but I don't want to look back in fifty years and think to myself, why the hell didn't I become a scientist/doctor/researcher?
Should I take the leap and go for writing? Or should I play it safe, and continue with health sciences?