How much alcohol can people drink?

I am a 40yr old female in good physical health. I typically drink 3-4 glasses of white wine a day. I felt fine about this amount until I did some searching on the internet and found that the CDC and several other agencies label that as "heavy drinking" in a woman. I have talked to many people, and it seems like many people drink 1/2 a bottle of wine a day. I don't know who to believe...the general population or the CDC. :(