Welcome SeaW -
Certificates ? In the US, not required unless working on boats.
Passage making can be a delight. I'd suggest taking the typical ASA or US sailing courses and then going on a charter for a long weekend - with another couple who has some experience. You don't have to go to the Carib. There are charters available all over the US, one might be close to you.
From the long weekend, then step-by-step take longer and longer voyages.
First, simple costal day trips where one sails only in the day and moors/docks in a marina at night.
Second step, a coastal trip with a overnight passage.
And so forth until one is comfortable sailing offshore for 7-10 nights.