Oomis:
What kind of people would have put such nonsense into her head?”
She said she has heard this all her life, no? So maybe family members have expressed this idea. Certainly, some of her friends seem to be a safe bet. Whether or not that is so, clearly it is on her mind, and a simple “no, it makes no difference whatsoever” would suffice.
Liora, if you are happy about this shidduch, then allow yourself to BE happy and excited. If you are looking for reasons to not be excited (my Dad, O”H would call them “klutz kashas”), then perhaps this shidduch needs to be re-evaluated. If you really care for your chosson and can see yourself building a life with him because everything else makes sense and is what you are looking for, then ABSOLUTELY NOTHING ELSE matters, and I give you permission to allow yourself to be excited about your upcoming marriage to your chosson. If you have doubts for other reasons, and they are merely manifesting themselves in this area, then you need to ask yourself some hard questions right now.