I think it is fear and seeing her for the first time. It's easier if there's some "problem" but "looks" are usually transient as, when we get to know someone, we don't notice their looks as much anymore.

My T was oriental and tiny and I felt like a bull in a china shop (small therapy rooms too), sometimes more than other times. It's hard if someone is "looking up" to us and we want to be able to look up to them :-)