I'm a water Tiger , and my lovely sweetheart is an earth Dragon.. I'm older than her by 15 years ..

Hisham,
If you were born on any day from 5th of February 1962 until 25th January 1963, you were indeed born in the Water Tiger year. As for your sweetheart, if born 15 years after 1962, she wouldn’t be an Earth Dragon. Depending on the day she was born, she would be either a Fire Dragon or a Fire Snake. In this case, the two of you would not match astrologically for a long time relationship, or marriage. You will have the same effect on her, as you would be pouring water over the fire. For her, to be an Earth Dragon, she must’ve been born in 1988, and you would be 26 years older than her.
Good luck to both of you.