Do I need an initial value? Can the initial value match the current balance?

You can absolutely have the same initial value and balance. So the below example is completely acceptable:

 A lot of gift card providers will only give you the balance when you do an export if you only have a balance column and no initial value column. If that's the case for you then there's a very simple solution. All you've got to do is copy the balance values into the initial value column and you're good to go. Reference the above example so you have a visualization of how it will ultimately look.