At your age the chances of it being cancer are almost nil. Skin cancer from the sun takes a long time to become cancerous, and that's assuming anyone actually gets cancer from sun exposure only as we are under constant onslaught from so many carcinogens and humans have lived in the sun most of their history. And this is on your feet. The biggest thing to look at with cancer isn't the existence of something, it's changes in that thing. Moles are common and harmless, but if they at some point start to hurt or change shape or color, that's when concern sets in, when it changes.
Hello, thanks for the question. If you have a mole or freckle that you think is suspicious, it is best to have it looked at. Sometimes a telehealth appointment can be adequate for this making it more convenient. Is this on the top or bottom of your foot? Truthfully, from what you describe, this doesn't sound like it has the characteristics of melanoma on the foot. Here is an article with pictures to help you. https://www.aad.org/public/diseases/skin-cancer/types/common/melanoma/signs-foot
Here are the symptoms to look for:
Brown or black vertical line under a toenail
Pinkish-red spot or growth
New spot or growth where you injured your foot
Rapidly growing mass on your foot, especially where you once injured your foot
Non-healing sore on your foot (or a sore that heals and returns)
Sore that looks like a diabetic ulcer
Get checked out but this sounds like actual freckling and not cancer Best to make sure of that though and let us know what you think.