Welcome Kazan
It´s looking good for your first skin
Imho the weathering could be a bit more "spiced up", from the colors and the shapes. (Photoshop...?) brushes are your friend for doing this

. Additional I´d suggest taking a closer look at photos like this one (just a result of a quick search...) :
http://www.jetplanes.co.uk/vintageai..._underside.jpg
ebo