Your risk of skin cancer increases with age. In the UK, most people diagnosed with skin cancer are over the age of 50; but this is not exclusively the case. There are also many younger people, especially those whose risks are higher e.g. due to significant sun exposure, blistering/burns in the past and/or family history of skin cancer.
If you are concerned then a full body mole check can be very helpful in putting your mind at rest, as well as acting as an early warning system for any suspicious moles that you may have missed in self-checking.