What mindfulness is not?

Mindfulness is not a cure, it is not magic, it is not a relaxation technique, and it will not solve all of your problems the moment you start practicing it.

Though mindfulness may help with many of those things, it will happen over time, and not instantly.
Many people have an understanding that mindfulness will help them forget about the past, stop thinking about the future, and be more calm and relaxed the moment they add it to their life, but this is not correct. While mindfulness can help you stop thinking about the past and the future and bring your focus to the present moment, this is a difficult feat to achieve, once that takes time, practice, and a lot of patience.

Mindfulness can help calm your mind through its various exercises, but like any exercise, it will also take time. If you start incorporating mindfulness into your life now, what ever your age is, that is the amount of years your brain has been allowed to do what ever it wants. It is used to that kind of life and freedom, and it will do what ever it can to continue like that, making your mindfulness journey more difficult.
It's because we cannot just override our brain's nature in a single session, or even in a few sessions. Mindfulness is a practice that can help change your mind's habits, it can help you have more control over your mind and the thoughts that enter it, and mainly, how you react to those thoughts and how they make you feel, but it just takes time.

This is a huge misconception many people have about mindfulness. They think it will be a quick journey, and when they see that after a few exercises nothing has changed, they decide it's not for them and that it doesn't work.

That is what mindfulness is not. It is not magic, and it will not solve your problems overnight.