Before she became a superhero, the heroine used to live on Earth in the USA. So she studied at school like the other children. She rode a bicycle and played baseball similar to a normal people. When she was an adult, she became a pilot in the US Air Force.
On an extraterrestrial planet, her DNA has been crossed with Kreel DNA. Then, she became a superhero with amazing powers like Superman: very strong, fly faster than a supersonic plane, her eyes could destroy everything with laser.
Finally, in the subway, Captain Marvel is fighting with an old woman who is in reality a bad alien with a human shape.