Why was it ok for an older woman and boy?

In Europe back then, 15 was OK for an affair. Note how many Europeans still think Polanski did nothing wrong. In the US, different story.

See Clare's Knee if you want to see a 70s French film that has a grown man chasing teens not shown as negative.

if man is 5
then the devil is 6
if the devil is 6
then God is 7
and if God is 7...

15? did we see the same movie?

It would have been torches and pitchforks, the complete program! xD

No seriously, you raise a very interesting point.
While in the court of law, both is wrong, culturally one is worse than the other.
Men "abusing" a young Woman? "Pitchforks!"
Women having an affair with a young Man? "Mh, well, but it's kinda romantic!?"

Tl;dr: Men are evil rapists. In any case. That's all we need to know.

Lolita is included on TIME magazine's list of the 100 best English-language novels to have been published from 1923 to 2005. It is also fourth on the Modern Library's 1998 list of the 100 best novels of the 20th century, and holds a place in the Bokklubben World Library, a 2002 collection of the most celebrated books in history.

Awards and honors
The film was nominated for a number of awards, including an Academy Award for Best Adapted Screenplay, and won a Golden Globe for Most Promising Newcomer which went to Sue Lyon.

Wins

Golden Globe Award for Most Promising Newcomer – Sue Lyon
Nominations

Academy Award for Best Adapted Screenplay – Vladimir Nabokov
British Academy of Film and Television Arts Award for Best Actor – James Mason
Outstanding Directorial Achievement in Motion Pictures – Stanley Kubrick
Golden Globe Award for Best Motion Picture Actor – James Mason
Golden Globe Award for Best Motion Picture Actress – Shelley Winters
Golden Globe Award Best Motion Picture Director – Stanley Kubrick
Golden Globe Award for Best Supporting Actor – Peter Sellers
Venice Film Festival Award for Best Director – Stanley Kubrick

The film received largely positive reviews and currently holds a rating of 98% "Certified Fresh" on Rotten Tomatoes.[22] Gary Arnold, in The Washington Post, wrote, "Manhattan has comic integrity in part because Allen is now making jokes at the expense of his own parochialism. There's no opportunity to heap condescending abuse on the phonies and sellouts decorating the Hollywood landscape. The result appears to be a more authentic and magnanimous comic perception of human vanity and foolhardiness".[23] In his review for Newsweek magazine, Jack Kroll wrote, "Allen's growth in every department is lovely to behold. He gets excellent performances from his cast. The increasing visual beauty of his films is part of their grace and sweetness, their balance between Allen's yearning romanticism and his tough eye for the fatuous and sentimental – a balance also expressed in his best screen play [sic] yet".[24] In his review for the Chicago Sun-Times, Roger Ebert, who gave the film three-and-a-half stars out of four, wrote, "Diane Keaton gives us a fresh and nicely edged New York intellectual. And Mariel Hemingway deserves some kind of special award for what's in some ways the most difficult role in the film."[25] Ebert includes the film in his list of The Great Movies.[26]

Alexander Walker of the London Evening Standard wrote, "So precisely nuanced is the speech, so subtle the behaviour of a group of friends, lovers, mistresses and cuckolds who keep splitting up and pairing off like unstable molecules".[27] Recently, J. Hoberman wrote in The Village Voice, "The New York City that Woody so tediously defended in Annie Hall was in crisis. And so he imagined an improved version. More than that, he cast this shining city in the form of those movies that he might have seen as a child in Coney Island—freeing the visions that he sensed to be locked up in the silver screen."[28]

In October 2013, readers of the Guardian newspaper voted it the best film directed by Woody Allen.[29]

Accolades[edit]
New York Film Critics Circle named Allen best director for Manhattan.[30] The National Society of Film Critics also named Allen best director along with Robert Benton who directed Kramer vs. Kramer.[31] The film was nominated for Academy Awards for Best Supporting Actress (Mariel Hemingway) and Best Original Screenplay (Allen and Marshall Brickman).[32] It also won the BAFTA Award for Best Film. In Empire magazine's poll of the 500 greatest movies ever made, Manhattan was ranked number 76.[33]

The film was number 63 on Bravo's "100 Funniest Movies". In 2001, the United States Library of Congress deemed it "culturally significant" and selected it for preservation in the National Film Registry. It is also ranked #4 on Rotten Tomatoes' 25 Best Romantic Comedies.[34]

American Film Institute recognition

AFI's 100 Years...100 Movies – Nominated
AFI's 100 Years...100 Laughs – #46
AFI's 100 Years...100 Passions – #66
AFI's 100 Years...100 Movie Quotes:
"I think people should mate for life, like pigeons or Catholics." – Nominated
AFI's 100 Years...100 Movies (10th Anniversary Edition) – Nominated