I say go for it. My hair is a bit shorter than that and it's been this way for over a year now.(before I cut it it was to the middle of my back. I have curly red hair)
Anyway, I LOVE the first cut you put up and I think it would look fantastic on you. Plus winter clothes look much cuter with short hair.
If you're itching for it then just go ahead and do it!
edited to add some recent pictures; I've had my hair cut since then but these are during August