Some of my family are YMCA Certified, while myself am PADI. We have been to different places in the world and have had absolutely no problem in getting them in the water. Don't worry about the Cert Card or organization. Just get through the program, then take your cert card and log book with you on your trip. Every commercially marketed program out there is recognized and is respected in some fashion or another. Many have organized and sit on the Recreational Training Standards Council, a division of ANSI, including YMCA, PADI, SSI, and so forth.
Just have fun and enjoy the training process. Get pumped about your upcoming trip and future diving "career." The main thing is to have a good time.
Happy Diving and Welcome to the Underwater World