I think this experience would be an important part of your overall narrative for your personal statement. If this experience was really impactful, which it sounds like it was, it likely influenced your overall educational path, growth, maturation, perspective, and motivation for medicine in some capacity. Therefore, even if you choose to discuss this in your other impactful information section, it seems these details about your personal background would be vital to detail in your personal statement.
Don't worry about whether your experience seems "serious enough" compared to others - admissions committees aren't ranking hardships. What matters is the genuine impact this had on you and how it shaped your journey toward medicine. Missing those foundational years of classroom learning and then successfully navigating your return to formal education demonstrates remarkable resilience and adaptability - qualities that are absolutely relevant to succeeding in medical school.
The key is focusing on the growth and insights this experience provided rather than just the hardship itself. How did this unique educational path influence your perspective on learning, perseverance, or helping others? Did it give you empathy for patients who face educational or systemic barriers? These connections to your motivation for medicine are what will make your narrative compelling.