Hi Brittany,
You can actually start using Little Reader once your daughter is 3 months old (some parents even started earlier than this, but it's really up to you). As far as distance from the TV/monitor is concerned, I'd like to clarify with you that the words are displayed in a size that's big enough depending on the screen size and on how long a word/sentence is. With that said, you don't have to sit too close to the screen -- sit at a distance that you think is just right for your baby, where you're sure she can see the entire screen within her eye level.
I'm sure many of the members here will have more tips too, so just try looking around the Forum or wait for their replies
