Latency Period

Ok, dumb question, is there a latency period with this or not ? You contact the CDC they say no, you would show positive if you were infected with HIV within three weeks of being infected, You contact the NAtional Aids hotline, they say the same thing, you talks to Drs around your area and they say , this stuff might not even show up in your body and you could show symptoms for up to 10 yrs before you know if you have it or not......... So what the hell, does anyone really know or what ?