Development of AIDS after getting HIV infection can take very long time depending upon your immune system. It can take up to 20 years after getting HIV with an average of 10-12 years. HIV positive does not mean AIDS has begun. After getting HIV, the virus can become positive in blood after 4-12 weeks and sometimes after 6 months. Symptoms of HIV appear after 2-4 weeks of exposure to HIV virus. AIDS can occur after very long time.