they have said that the gudiya factory incident was 17yrs before so accordingly it should be
asad : he was 8yrs old when this incident took place so now he must be 25
ayaan: he was almost 4yrs so by now he will be 21 { humeira said that when she was missing it was his b'day and also gaffor once said that he has finished his graduation}
zoya : she was only 3yrs at that time so by now she would have completed 20yrs of age and going to be 21yr old { as per the spoiler her b'day is coming up}
najma : since she have completed her graduation she should be around 20yrs
nikhat : since najma and nikhat was doing final year in college she also should be around 20 { they have said najma is the elder daugther so may be she is only few months older than nikhat}
humeira : around 19yrs { in the intial episodes it was said that she is doing second year in college & they have also shown her b'day after ramzan}