It is never too late to file a VA disability claim. Claimants are not limited in the number of disability claims they may file. But there are important distinctions to keep in mind. For claims seeking service-connection, the VA calls them original claims, and once they are denied and become final, all other claims are called claims to reopen. As for claims seeking an increased rating for a service-connected disability, these type of claims are called increased rating claims.
These distinctions are important in assigning effective dates for disability awards. Remember, effective dates cannot reach any further back than the date of the claim. So while any number of claims may be filed for a service-connected disability, an original claim will have a potential effective date earlier than a claim to reopen.