What are the chances of me getting into GT?

i'm a yr. ahead in math...but i'm not good at it anymore...my grades are declining...i'm in four ap cles this yr. as a junior and i took one last yr. also.....my GPA so far is a 3.8 i have plenty of extracurricular activities, and only two sports...but my sat scores are low...like 1800 out of 2400....actually that was psat..but.does that limit my chances of getting in?