Ciara,
You are right. Your hair should be a non-issue. It's not like the fellas are planning to come over to shampoo your hair, then blowdry and style it...
While colour is important to many men, I really doubt that any right thinking man is going to be looking at your hair and thinking "hmmm, now if only she had black hair" when you are deepthroating him. He is more likely to be grabbing your hair and looking up towards the ceiling saying " Oh God....".
Be seeing you soon, hun.
Regards.