in 2005,i had sex for the first time .In 2008,Decemeber,i was just diagnosed with CD4 300 or so.I learned that many people drop to 300 in 7-10 years,why am I in such a fast progressor?

The most important factor that determines how fast HIV spreads is the height of the viral load in the blood. The higher the viral load, the faster the CD4 drop. Also, there is a wide range of "normal" CD4 counts, some people start out lower than others. Another time that CD4 counts may drop quickly is right after becomming infected with HIV, this is called "acute HIV infection"..at that time the viral load is very high and the CD4 count can dip low. After a few weeks the viral load stablizes at a lower level and the CD4 count can come back up a bit. If you have just been infected in the last few weeks (did you have a bad cold like the flu that lasted a few weeks, perhaps with a skin rash or sores in the mouth?) that might explain the low count. It is very important to have follow up testing done and if it is confirmed you should plan to start treatment soon.

Good luck, Joe