Initial cycling without sump

Hey, so I'm about ready to start my tank and am pretty sure I want to use a sump but am not 100% sure yet. I'm wondering if it's fine to start my initial cycle without a sump, and then add one later if I choose. Would it be bad to add a sump (and the additional water required) in the middle of cycling?

Just for reference, it'll be a 30g reef tank with a 10g sump.

Thanks!
Cody