When you consider the future of your healthiness, you will begin to make a medical plan. To make a medical plan you have to pay a fee. Usually, a medical plan made by your local government is free of charge. But if you use a medical plan from a paid insurance company, you have to pay. After that you will receive a medical card for free so you can get medical treatments when you need them.
In order to have a medical card, there are various requirements that you should have done. Medical cards are made based on the background of life you have such as age, occupation (in the registration form, the salary that you get in your work will also be included), the number of family members, valuable property that you have (ex: house and car), also includes savings. By filling out the background form that you have, then it will enter the review stage to adjust the medical card that you will have. Don't worry, the data you fill will be archived properly by the medical plan maker.
Until now the regulations related to the age of having a medical card in each country are different. However, people usually need a medical card when they already have a job. So, for those who are not yet suitable for work, they can not have their own medical card. However, they can use a medical card that is owned by their closest relatives. Because with the medical card, the company where the person works can help covers the health costs of that person. So, if you are 17 years old and have a job, of course, you can have your own medical card.
You can keep your medical card as long as you have a job. Even when you stop working, you can still save your medical card with a time limit of 3 years. But is it possible that within 3 years you will not work? Maybe in 3 years, you will stop working for a while then start again in a different place, it is still possible for you to have a medical card. But if you haven't worked for 3 years, your medical card no longer has any meaningful function.