SharedObjects() help!

I want to pull into an SO the date that user first visits the site.
I have tried a variety of methods, but the info is not getting into the SharedObject or the info is being overwritten with the current date everytime the user visits the site.

I have tried declaring my variable thus :

var memberBegin = new Date();
memberBegin.setDate = now;

From a variety of searches, I think that I may have to pull in the info from Arrays that set the date, month, and year which I am using to populate a text field ( display.text) on the main time line. How can I pull elements of these arrays into my sharedObject so that the date of the users first visit is recorded ?

I should point out here that I have no problem writing arrays ( as in the above example) and I know how to create an SO and populate it with data, I am just having a problem recording the date as stated above