What does it take to succeed in this dive?
SCUBA diving is a really cool sport / activity / adventure because virtually everyone can participate, even if you are disabled.  There are so many stories of SCUBA diving being used as therapy for disabled individuals.  Those who can’t participate are typically those who have lung problems, breathing issues, or problems equalizing their ears under water.  
In other words, it is not hard to succeed in this dive!  You can probably do it, right now if you want to.  Sure, you’ll need a medical check prior, to ensure you are healthy (you are, after all, about to go breathe underwater), but in general, you can probably try it just the way you are.
Of course, the more in shape you are, the easier it will be.  
And in order to actually get certified, you will need to find the money and discipline to take the training course.