1- The younger does not have to ask. The parents could have a discussion.
2- Maybe the older should think about Emunah. Each will get his or hers in the time ordained by Hashem. Giving or witholding permission may be getting involved in an area and in a way we should not be involved. Maybe we need to leave it up to Hashem who will /will not and when.
3- Maybe in shamayim there is a some negative issues which is preventing the older from getting the shidduch he or she is waiting for and “not being makpid”. no……. more than that, GIVING permission willingly and happily may be the chessed and zechus which breaks the “hold” in shamayim and will be the cause/effect for the older to find his-her shidduch.
Hatzlacha to all…….. younger, older and all in between…. in whatever order Hashem chooses!