Faramir is a boyfriend for a grown woman. In our world - and let's take him out of his medieval context for a while - he'd be unlikely to be going out with a girl who wanted to spend all her time in nightclubs, but he's a kind man. If he did find himself clubbing, he'd make her evening enjoyable,get her home safely and ease her out of the relationship without too much pain.
But he accepts Eowyn for who and what she is. She has decided to retire from fighting and become a healer, but if she wanted to continue as a fighter he would support her, though he himself sees fighting as what he does only because it's necessary.
He strikes me as the kind of guy who would remember your birthday; as someone whose passion is historical research it is likely he'd be good with dates. I think he would take you somewhere pleasant to celebrate, perhaps a nice little Gondorian restaurant where the waiters knew him and the food was great, and give you all his attention.
At the same time, I can see him as someone a writer or scholar could go out with on an ordinary evening. Both of you could take your books and laptops and eat whatever was brought out while you write and he researches, never thinking you're being rude or being annoyed because he has his nose in a book.
There is his Dad, of course; I suspect Denethor would never have approved of Eowyn as a daughter-in-law and would be just as unlikely to be happy with a "bluestocking" in his son's life. Probably just as well he's out of the way by the end of the book.
I have read that Faramir was Tolkien's alter ego, but Tolkien was not really a very good husband. He used to leave his wife till two in the morning while he was out talking shop with his scholarly friends. Yet I think Faramir might have a word or two to say to his creator about how to treat your woman!
So, though there are some YA heroes I'd consider - Peeta, perhaps, Michael Pryor's Aubrey Fitzwilliam or his friend George (who can cook!) this is my first choice for a date.