Most Helpful Guy
This is my experience, having had two girlfriends who dyed their hair red (and required my assistance with it).
The red color you're looking at will require you to bleach your hair first, and then it will require very frequent redye efforts to keep it from looking faded (about every 10 days), because red fades very quickly with light hair. You could dye it red without bleaching, but because you have dark hair already, it's going to be a pretty dark red.
If you're down for that, go for it, but it's a lot of work.1