Sometimes information on petit mal or seizures is difficult to find on the internet for your specific case. Some people can have accidents of various kinds which result in some kind of an injury to the brain or a trauma and then all of a sudden you may start having seizures, either petit mal or of another kind.
This also does not have anything to do with your age. A teenager can develop seizures just as well as an elderly person, however, there is a much higher chance of the elderly to have an accident due to age and physical condition being weaker to cope with injuries.
The truth of the matter is that any kind of injury to the brain can have a whole range of consequences which are impossible to predict. Also they can manifest themselves immediately or after a long time. Petit mal or other kind of seizures are one of the types of consequences you can have after a brain injury.
If you think this has happened to you or you suspect something strange after an accident do yourself a favour and check with the doctor and also have an EEG scan performed to verify what exactly is going on.