Left is ALWAYS better than right
So you are on the good track and your friend is correct.
Now the difference is if she is facing up or down...nonethe less, even if face up left is the side you want...for some reason baby's like corkscrew through the birth canal...they dont just "drop down" like most ppl would assume, and so the idea is that if the baby starts on the right side, it has so much more turning that s/he has to do.(which inevitably means back labor because the baby has to turn the entire way around, hence meaning at some point the baby would be back to back...which isn't fun
) The left is the most ideal because it means the baby doesn't have to cork scew as much
Currently my baby is OA (which basically means he is head down face down, but his back is in the very center of my bump) but im a okay with that because that is also ideal
So long as baby isnt to the right side and so long as baby is head down face down, im a very happy girl lol