Tell me about a time your estimate was significantly wrong and a deadline slipped. How did you communicate it, and how did you adjust?

Imagine you promised to finish a big Lego set by dinner, but halfway through you realize there are way more pieces than you thought. You have to tell your parents you'll be late, explain why, and figure out a new plan to finish it together. That's what this question is about — how you handle missing a deadline and keep everyone on the same page.