It will lighten, just wait a week or so and you will love how it looks. You should also do the strap so they match. The color will be a bit deeper than it was but it will look better after a bit I promise! I often use this on light, older bags and it always looks horrible at first as it goes on unevenly, you get streaks and blotches. Then they just disappear after a few days and the overall color is more even and richer.
I concur!