Absolutely not. Training will improve your fitness and body conditioning, but you do not need a baseline of fitness. Training is always taken at your own pace (though with encouragement to push yourself) and adaptation is a key part of what we do, so techniques can be altered in order to make them more accessible to you, until you are ready. You are never too old to start training. Some students start as children and move up to adult classes, some students don't join until they are already retired. Please speak with your instructor about any injury, disability or difficulty which you may have before the start of your first lesson.