That's great! But why wait so long?Funny! My son just called me. He has signed me up for an open water certification course in Houston this January!(We are going to Costa Rica for a couple of weeks a couple days after the course...think he's looking for a dive buddy?
I get the impression that you have a thirst for knowledge, so I'm going to recommend some material to you that will help you with your open water course (and some questions to ask your future instructor(s)) and additional diving info.
Jim Lapenta's book: https://www.amazon.com/SCUBA-Practi...&qid=1478271144&sr=8-1&keywords=james+lapenta
Andy Davis's website : Sidemount Technical Wreck | Andy Davis Technical Diving Philippines (great blog and articles)
Cave Diver Harry's website: Cave Diver Harry (great blog)
And people, let's encourage him. @Aqua Llama isn't looking to raise a family and send his kids to university from his income as a scuba diving instructor. I think he's happy just to have some income to reduce the amount he takes out of his retirement, and this is certainly doable. And he will be marketable with dive operations that want a stable instructor that isn't going to try to sleep with every attractive female client that they come across. He's not some clown with no life experience and no clue.