Hi Trish
If it was standard ballroom comp, your height probably would count a little bit against you. The general 'appearance' of the couple is what the judges first see. Obviously, the whole thing is very subjective, but our coach has told us that in the preliminary rounds, there are so many dancers that all a judge can do is look at the 'shape' and appearance of a couple - their hold, carriage, movement, rhythm.
There's a good discussion of this at:
http://www.dancesport.uk.com/articles/index.htm