Iíve been PADI Advanced Open Water certified for 40 years
Learned in college, 20 hours classroom, 20 hours pool,
2 Open Water dives FOR BASIC, The classroom stuff was like a physics course.
Many more dives for the rest, had to perform all sorts of underwater tasks.
If I were you
First thing Iíd do would be to jump in a pool and do a 400 yard swim
With your face in the water No Mask just a snorkel.
Being a safe diver starts with being a good swimmer with good
In my opion, as was stated by a previous poster Most recent certification
schemes really donít teach enough to keep you out of real trouble.
I remember having to solve all sorts of scenarios such as
Start in NY with a dive to 3 atmospheres, Fly to Denver do a same day dive to 2 atmospheres
That night fly to the Caribbean ,next day do a morning dive to
4 atmospheres and a following night dive to 3 atmospheres,
Fly back to Denver then drive into the mountains to 12,000 feet
And do a cavern dive to 4 atmospheres.
Solve for bottom times at each location and a go or no go for the scenario
And state why.
I can no longer do these But am Aware of the issues and All divers
should be. Thereís learning to be a safe diver and then thereís learning
Just enough to get you killed.
In answer to your question
Iíd start a soon as possible and build experience and let everything have enough time to sink in.
: Weight belt goes on last
Now that Iím older I just limit myself to 1 atmosphere in depth
and donít worry about anything, also very fond of free diving without the
70-80 pounds of gear