i'm trying to figure how many days i've been playing sto. . .how do i find out the exact number of days i've been playing? anyone know?

You go the main website and click on Account there. That will tell you how many days you've been subscribed.

To find out no much play time each character has type the command /played into your chat window. It will display much much cumulative play time the character has in days, hour and minutes. Of course , you need to do that for each character and add 'em all of.