Hi mate.
Being 22 and having had 2 procedures, i can totall relate to you. I am(was) probably a diffuse NW5.
Truth be told, if you told me that your frontal 1/3 was totally barren and that the middle and crown were holding up nicely i would be reluctant to suggest a ht. But us with a diffuse pattern have the advantage here, as the future loss is much easier, although not entirely, to determine. Hence, hair can be planted inbetween to create density, and even if the remaining falls off, it will not create an unnatural gap, it will merely look thinner than before.
This being said, i am not a doctor and i cannot tell you if a HT is a good idea for you.
Could you show us some pics? 4k grafts is around the same as me (4.3k)