What am I supposed to draw when I'm starting?

This winter for the 2 weeks I had a break from university I started learning drawing. I did the first lesson of drawabox. I haven't drawn anything since, and I've always been scared of drawing from imagination, as if I'm scared of not having good ideas or not being creative enough. Do I draw from reference? Do I keep going with drawabox or do I start over? I don't have an issue with drawing badly, it's moreso that I'm scared of not knowing what to draw. I'm not used to doodling or drawing for fun, so I don't even know if I should be learning this when I'm not already naturally doing it out of personal enjoyment, but I often look at drawings and have the desire to be able to draw like that.