That's funny, I voted, but my vote didn't show up in the tally. And the tally is zero for both categories. Weird.
You natural haircolor is identical to mine. I went natural throughout most of my twenties, but since my thirties started, I've gotten bored and have been messing with the color.
If you're going to color it, you're going to have to accept a certain amount of damage and/or awkward phases. Just know that up front.
I did henna for a couple years and it's wonderful for conditioning, but it never
fades. You can lighten it with a few different techniques [I used ColorFix] but there will always be some color left.
So once you're done with henna, you'll need to figure out how to transition out from that. The best way would be to cut the hennaed part off. I'm trying to sort that out myself these days and it's not easy. I really like the length I have and it took years to get it this way. I could go darker with a demiperm, but it really doesn't suit my coloring.
Also, the demimpermanents can sometimes be more like permanent colors on curly hair. I've read here where more than one curly has had this problem, ie., the color never fades.
Anyway, you can see what coloring does to a person's options!
You could get some subtle professional highlights done. That way you can see if you like them, the damage will be minimal, and you can grow them out very gracefully.
Don't let them talk you into anything more involved, like all-over color. This makes it more likely you'll need to return to them for root touch-ups, but if you just want the highlights, be firm with them. I had a colorist do the highlights I asked for, then she talked me into a "glaze." Well, that just turned out to be all-over color that when it grew out, left a line where my natural color was. I think she was just trying to ensure I'd return to her.
If you decide to go with all-over color that you do yourself, I can highly recommend Robert Craig for a gentle color shift. It's not going to do anything dramatic, and it won't lighten, but it's a nice subtle change.