Eyebrow pencils can be hard to match for a blonde. Most are too copper, or too grey.
I'm a dark blonde, way ashy (is it mousy brown? Is it mousy blonde? I don't know). This was recommended to me by the fine people at reddit's makeupaddiction forum. I bought a couple of other items to try. In the end my "brow solution" is:
1. This pencil - brush end.
2. This pencil - pencil end, first check if it needs sharpened, then gently outline the shape I want. Some days work out better than others hah! This isn't SO dry that you can't smudge it into a better shape once applied. Hence I follow it with a few other items.
3. NYX brow kit for blondes. This comes with a little brush, 4 colors (including an off-white highlighter), and a few stencils in a nice "stretchy band keeps it shut" package. I actually use their stencils that come in it and the color in the bottom right. I was skeptical of the stencils, but it really works.
4. NYX brow kit - the highlighter part. I take the brush in the highlighter and apply a bit of this around the whole outline of my brow to give it a sharper defined edge (better than drawing my edge of brow lines super sharp which would look too drawn on). A little extra goes under my arch on my brow bone.
5. e.l.f clear brow gel - just to hold the hairs where I had them.
Hope you have the same good luck!