I'm still working on my first sweater and have been for 2 years now! (I'm just not motivated to finish the sleeves). I admire you doing this without a pattern!
I love the details & color blocking. I think the hard thing with a light yarn and a first project would be showing any "problems" that you encountered along the way. In the pictures you show, I can't see anything though. It fits beautifully!
Maybe I'm inspired to finish my first sweater so I can start one for myself!