A 12 year old girl weighs about, what, 80 pounds? But sort of awkward to pick up, so I think it checks out :)
Tall ones (taller than me) can get up to at least 130.
It doesn't take a lot of forearm strength to hold a bar on your shoulders. It takes a LOT of forearm strength to bring up 415 resting on your fingertips.
Avoid putting the barbell high on your shoulders or you risk back pain/injury. Put the bar on your traps and hold it place with your hands. This is what makes it a full-body exercise.