Learning Martial Arts is something that stays with you lifelong and is not always connected with being used as a combat style but can also be learned to keep fit or just for the fun of being good at something that might come handy in rare situations only.
But when you decided onto the fact that you do want to learn it after all, do not hesitate and the first step towards this goal would be to decide which style would suit you most.
It has been found that for younger people with a more flexible body; Wushu and Kung Fu styles of martial arts are the most suited while for older people, Taichi would be a good choice. But if you are one of a burly physique, Karate and Tae Kwon Do should certainly be your style.