Very good!
Not easy to get the seaming so neat, I'm guessing you've been around a machine a fair bit even if this is your first garment! I've done a fair bit of pattern cutting and as long as you avoid changing seams where there is a shaped part attached, OR make sure you balance the adaption on each piece, you shouldn't go far wrong.
I'd avoid alterations where theres a collar attaching and armholes can be slightly difficult (tis better to cut right across front and back halfway down the armhole if you have to make the armhole deeper so they are the same front & back and just smooth out the lines but then you gotta try and add in to the sleeve head
6oz, bet that'll stand up to heaps of running through hedges!!