3 year vs 4 year offer

Hi,
The status on my application page indicates that I am a winner of a "3 Year Advance Designee Scholarship". I am currently a HS senior, looking forward to four years of college. Does the Army offer 3 year scholarships to incoming college freshmen? Is there any chance it could be changed to a "4 Year Advance Designee Scholarship". Insights and advice would be welcome!