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Over the course of many months, a subdural hematoma typically stabilizes, organizes and liquifies, in a sense, to the point at which symptoms would on longer be expected to arise de novo. The only way a chronic subdural would become symptomatic after so many years would be if you rebled into the area damaged by the original hematoma. Being on an anticoagulant now would be a risk factor for this. The easiest way to find out the status of any suspected intracranial bleed, of course, is to get a CT scan. This would be particularly helpful in the setting of new neurological symptoms that have no other readily apparent explanation.
This reduces the chances of a rebleed, of course. Other risk factors include being on aspirin or longterm abuse of alcohol, certain medications, recurrent falls, or prior intracranial surgery. Otherwise, your risk would be about the same as the average 26 year old, which is to say very low.
If you have no other risk factors such as those listed, you would have about the same risk as any other young person your age. Your prior head injury may increase your risk slightly, particularly if the subdural was large or there was damage to the adjacent brain. Some brain injuries do lead to shrinkage of brain tissue or replacement of brain tissue with fluid (encephalomalacia), which can put a person at increased risk if they suffer another head injury.