EliasG, you're young and "new to this stuff", so here:
To get your initial Class I, you will pass if you are healthy. There are a number of medical conditions which will exclude your passing. Most of them relate to vision, neurological conditions, and a long list of chronic diseases which are fortunately not that common. Psychiatric conditions, addiction to drugs or alcohol, etc., are common causes of failure.
There are also a number of less severe or temporary conditions, for which you need to have proper treatment, then they re-evaluate you and if you then pass, you're good to go. Obviously, if you have a broken right arm you will not pass, but when it's healed you will.
At your age 17 it is hard to grasp the idea of illness. Most young folks, if they have not had much medical history by your age, will find initial passing not that tough.
Keeping that medical requires that you keep your health. As we get older, the most common causes of poor health involve weight, blood pressure, smoking, and drugs and alcohol. Best not to let any of those things get out of control. These days a big problem is the number of people taking psychoactive drugs: for depression, ADD, or whatever. Some authorities will approve in some such cases, many will never approve.
And remember, the important thing will always be what the authorities think of your health, not whether you yourself think you're okay to fly.
So it's like what others have posted. Stay healthy, and if you wish to fly for a living, don't allow any of those things to get out of control.
Graham MD