Important for what? In terms of employment, you need both. If you don't have an education, many employers don't care what your life experience is. You might have written several books and know everything there is to know about your industry, but if you don't have that diploma your application won't even get looked at.
On the other hand, education without experience doesn't get you very far either. In today's hypercompetitive job market, having a diploma just lets you in the door. A diploma alone doesn't give you much advantage, because everyone else applying for that job has one too. Without some experience to separate yourself from the pack, you won't get anywhere.
Life experiences are certainly important, but they shouldn't be pursued at the expense of education. There are plenty of ways to get life experience and pursue an education at the same time. Become an exchange student, volunteer, take an internship, travel in between semesters... There's really no need to choose between life experience and education.