There are a number of factors that could make it essential for you to consider embarking on the weight loss journey. It could be a honest realization that your weight is too much, and that being overweight in that way could (quite inevitably) cause you major health problems in latter days. So instead of subjecting yourself to the physical and psychological agony, as well as the likely financial pressure of such health problems, you simply decide to take a proactive step - by way of weight loss - to keep those health problems at bay.
It could also be a case where your weight is relatively healthy, but where you still feel the need to cut it down in order to look good. Some would term this as frivolity, but the truth of the matter is that we are human and we want to be seen by 'significant others' in good light. We also happen to be living in a society where being slim is seen as part of what goes into being 'good looking.' So your body weight may be relatively healthy (in strict medical terms), yet not very attractive (in aesthetic terms), making it essential for you to embark on the weight loss journey, in order to improve your aesthetic appeal. To an emphatic person, this wouldn't be termed as frivolity.
Now as you embark on the weight loss journey, there are a number of things you need to keep in mind. One is that weight loss can be difficult. Knowing this right from the outset puts you in a better position to cope with the difficulties of the journey, increasing your chances for success - as compared to the person who expects the loss of weight journey to be a walk in the park. The latter person, approaching the weight loss journey with such obvious naivety, would be in a for a very rude shock; which may make it impossible for them to proceed with the journey when they discover that no part of it can be truly said to be exactly easy.
The second thing you need to keep in mind, when embarking on the loss of weight journey is that, the difficulty in its attainment notwithstanding, weight loss is still a possibility. There is really no reason as to why you should not lose weight, especially if it is weight that you put on 'artificially' at some point in your life. When you don't seem to be making any progress on the journey, what may be necessary for you is to change tact or find a way of motivating yourself - but you shouldn't let yourself come to the conclusion that loss of weight is impossible, because it simply isn't.
The third thing you need to keep in mind, when embarking on the weight loss journey, is that the loss of weight journey - its difficulty notwithstanding - can also be a greatly rewarding journey. This is about keeping your eyes on the prize (the rewards you stand to earn if you bring yourself to successfully complete the journey) and it can be a great source of motivation in your journey towards weight loss.