What is the significance of the poem A Sweet Sad Turning Of The Tide by Maude Meehan?

(This is the poem)

My Two young sons

move with assurance

through the maze

of ropes and sails,

steer out of turbulence

to calmer seas,

drop anchor .

They climb the mast;

my body tanses

with past apprehension.

Suddenly one dives ,

I plummet with him ,

breathe again

when he emerges

The small boat pitches

as he hoists aboard.

I glance up swiftly

to the swaying crossbeam

where his brother

perched, confident .

As heavy mist rolls in

they guide the light craft

back to the harbour , and like my hands

old maps lie folded on my lap .

Reaching the laddered dock

they stretch strong arms

to steady me. When did

this turnabout occur?

I have become a passenger

on their journey .

What does it mean?