Hi,

There is no as such minimum or maximum age devised to undertake the SAT Exam. So, even being, 19+ , you can sit for SAT Exam. There would be no problem at all. Generally, the SAT Scores are taken for admission  into the various undergraduate programs in US and few other foreign countries.

Know more about SAT Exam over here: https://studyabroad.careers360.com/articles/sat