SAT exam evaluates students knowledge on the basis of reading, writing and quantitative aptitude and other specialised subjects.

It is taken for undergraduate admission in the United States and some other countries.

As such there is no eligibility criteria and age limit in this exam but students are advised to take the test when they are in senior high school.

The SAT test is offered seven times a year in the US and six times internationally. There are two ways to register for SAT- Online and by mail. Although, registering online is the quickest way to apply for SAT, you have to register by mail if your age is below 13 years. Candidates may select their preferred test centres and dates while registering for SAT on the College Board website.

To check in detail about the exam you can refer below link

SAT Test

Good Luck!!