It's not necessarily overexposed, but the shadows are blocked up. If there is detail there is the neg/raw then I think you ought to work on pulling it out. If there is not, then I do believe it's overexposed. The white shrubs appear almost entirely in zone 8. As such, they're lacking detail. The mid-range detail is very nice here, but I think the shadows are problematic, and while you nailed the sky and background exposure, it leaves a little to be desired in the foreground highlights.
I just dikked with it too much. I liked the color version just fine (despite some minor composition issues- touching and stuff). I don't know why I messed with a conversion. Maybe I should take a day or something.
Here's the original color taken with a nikon 990, April 2000;