Every health insurance provider is obliged to insure you under the basic health insurance package. Your health and age are irrelevant. The health care covered by the basic health insurance package is the same for every health insurance provider. The cost of premiums may vary depending on the provider, so do a bit of research.
Two admirable things that people from other countries might not appreciate enough about the Dutch system. #1 Children under 18 years of age are insured for free, and #2 every person, regardless of means, has to have access to medical care.
It is your own responsibility to get a health insurance policy from a health insurance provider. Payingit International offers a collective health insurance at reduced rates for its employees.