You don’t need more time, you just need to decide.
Some of the most innovative products or influential works or art out there WERE built in a day (or close to it). John Grisham wrote a best-seller in a day. Willie Nelson wrote his three best songs in a day. The first version of Facebook was shipped in a week. The best salesperson on the floor doesn’t think about when she is going to do her next call, she just calls.
Chances are, you're way more prepared and further along than you think. Sure, you might break stuff—in so doing you learn way more than you ever could by not trying in the first place.
Here's another one you hear a lot:
This one might be more difficult to apply to relationships, which might sound more like "move fast and build things." Where, in this case, the 'thing' is the person. In any event, it's your job to drive the relationship, process, product, or service forward. And, again, you don't need more time, you just need to execute.