If an e-ID can vouch you are citizen number #3223423, it should be able to use the same crypto to vouch that your birth date predates a threshold, without revea

If an e-ID can vouch you are citizen number #3223423, it should be able to use the same crypto to vouch that your birth date predates a threshold, without revealing anything else. It's more a question of requirements gathering & UX (and political will).