My ‘source’ for how and when they met is Ivanka, who I have known personally for a decade. Your ‘sources’ sound like they hang around high class locales such as female dressing room toilets and the bar stools at strip joints.
Just a tip but I hear Hillary is seeking a friendly profile. I’m ‘told’ she’s keen to label it ‘The Harridan in Action’. Hey, give your ‘sources’ a shot.
http://www.cnn.com/videos/us/2015/08/13/melania-trump-profile-kaye-dnt-ac.cnn
Melania herself said she met him in 1998 in the interview at the link. Her birth year was 1970, available all around the internet, which means she was around 28, not 40, when she met Trump.
You can dispute and disparage all you want, but you can’t change the facts as given by those who took the pictures of Melania or by Melania herself.