you ever got past puberty.

Hi.

From a movie I watched 'The Rock.'

Mason, who once was a trained British operative
gets to be involved in a mission with an FBI agent, Goodspeed.
During the mission, Mason keeps saving Goodspeed several times.

All the threats are neutralized, and Goodspeed launches green flares,
only after a bomb is dropped on.

Mason, once again pulls Goodspeed out of sea water, preventing him from drowning. And he says,

-----------------------------------------------------
I'm fed up saving your ass.
I'm amazed you ever got past puberty.
I suppose all this will make
a great bedtime story to tell your kid.
-----------------------------------------------------

Mason was kinda joking, I think, when he mentioned 'puberty' here.
He meant, I suppose, I'm amazed you are still alive or something.

What could he possibly mean when he said,
'I am amazed you ever got past puberty'?

Thanks.