Am not yet an amatuer diver but i will tell you a small advice based on my little experiance.
Your Open Water Course is your first course that gets you into the sport of SCUBA diving and is the minimum course you need to use our dive gear. There are a number of different certification agencies that offer open water courses including SSI, PADI and CMAS. All of these courses are internationally recognized and each organization recognizes each others certification. There are a lot of arguments about which certification agency is better.... but realistically the quality of any course is dependant on the quality and experience of your instructor and the number of dives you do during the course. More is obviously better for both. Before you begin your Open Water Course you will need to pass a Diving Medical Examination. I hope this can help Jeanna