“coee” looks like it may be a typo or nickname, so the safest general answer is: most students get out of high school at about 17 to 18 years old, though the exact timing depends on their birth month and school system.

What that usually means

  • In the U.S., high school graduation typically happens around ages 17–18.
  • Some places have a specific final-day date for Year 12 or senior students; for example, one education authority lists finishing dates in November for Year 12 students.
  • Because of that, two students in the same grade can finish on different dates or at slightly different ages.

If you meant a specific person

If “coee” is a real person, the answer depends on their school, grade level, and country. For a more exact answer, the full name or school context would be needed.