Never thought I'd race under a Peugeot banner, but this livery is just too good. You're modest when you're saying this is your first mod and you're not quite used to the modding tools yet, you've blown 95% of all liveries on this site out of the water.
If I had a little suggestion, try adding a little bit of yellow that you can see from the back. When following your team mate, the car looks full gray/black. A nice yellow bar on the rear spoiler or diffuser would be really good.
Can't wait to see what you come up with next!