@amazingme if you do decide to go with demi-perm, it will help to tone out the brass that you don’t like. Just mention it to your hairdresser, she’ll know what to do.
The nice thing about demi permanent is the way that it develops looks so different from a permanent color. Someone once explained it to me like this : If you have a piece of natural wood and you paint it, all of the grains and underlying tones disappear under the paint. That is like permanent hair color. However, if you varnish the wood, you still have the natural tones and grains shining through, only with a new glaze of color over top. That is like demi-perm.
Anyhow, I hope you don’t feel like I’m pressuring you. It is your hair to do with as you choose, by all means. Just throwing my 2 cents into the mix. :)