Satyesu, this is another one of those times where I'd suggest:
1) Just write. Getting that draft on paper at this point may be more important than worrying about genre at this point.
2) Read read read. If you're reading books across a variety of genres (including NA), you'll be able to better determine if your book fits in with other NA books for marketing purposes. You also may have a general fiction book with a 22 year old protagonist.
+1
Seems to me you have a choice here.
Do you want to chase the market and write something that will be popular above all other considerations? That's likely to be a losing game. You know how sunlight takes about 8 1/2 minutes to reach Earth? By the time a book hits shelves and you see it, it's been possibly a year or more since the story was subbed and accepted, let alone written (add on possibly another year or several here). So, barring insider information, you're chasing an illusion, like the apparent position of the sun.
Do you want to write you story in your head right now, to the best of your ability - something that speaks to you, that you yourself would want to read? Then start writing. Keep reading, of course, and be ready to consider how you want to pitch it, but just start writing.
Either way, you can't sell a story unless you have a story to sell.
(Again, I might suggest you seek a writing mentor; IMHO, there seems to be something holding you up/back or something in particular you're seeking, that you keep finding reasons not to start writing just yet, and that may require more intense and personalized answers for the breakthrough you need. I can't help feeling that we're not quite understanding what you're asking for.)
