Environmental factors, such as friends, family, and the media, have little influence on whether or not someone chooses to drink or not to drink.

This is false. All of these environmental factors can impact your decisions greatly. If you don't have many friends, and good relations with your family, you may feel very depressed and think that the cure for depression can be found in alcohol, which is rarely the case. So, everything around you can affect your decisions, but ultimately it is you who decides - you should know what is best for you.