Please allow me to respond with an even better question–
What is your opinion of a girl who is concerned enough to inquire about a girl dating a guy – (GASP! Please wait a minute while I get the smelling salts…) – who is the same height as her ???
It’s entirely in the eye of the beholder. Some people care, some don’t. Decide for yourself if you do or you don’t, and don’t care what others think about it.
It’s perfect if you’re going to build your own house. You save money by making the doorways just high enough for both of them. Unless they’re both very tall.
There’s no problem with it. There’s even no problem with a girl marrying a man shorter than her. It does happen sometimes. As long as the girl is still attracted to him and he is secure enough to feel OK about it, there is no problem with getting married. 90% of the time the husband is taller than the wife, but there are always exceptions, and they probably work out fine most of the time.
What’s on your “top 5” list? Decide for yourself which 5 things are non-negotiable. The rest you can decide, case by case. If height is non-negotiable, then that’s your answer.