Hi,
On my 19th birthday I had the knowledge of a fifth grader (teacher’s assesment). I spent 8 hours per day studying math, english, and various sciences. I am 20 years old now and have completed a pre-calculus course and taken the SAT math level 2 to score a 670. It is never too late. You need a good teacher and a determination and willingness to learn. You’ll be caught up in no time.