Do you think this was a hilarious joke?

[Sime]

My best friend and I saw Avatar the movie (not air bender) together and I made this joke after the credits "they should play the Blue (Da Ba Dee) song by Eiffel 65 at the end of the credits" i laughed and she did too but then i notice her laughing a lot longer than usual i look at her and said "what?! whats so funny?" i for a min there i thought she was laughing at something else until she pointed at me then i knew she was still laughing at that joke i made. i didn't think it was that funny! why was she laughing so hard? btw im a girl