All in all you look good for not having a lot of experience. It's hard to tell from this angle, But I'm suspecting you are jumping ahead a little. What I would want to see is your stirrup more on the ball of your toe rather than the center, allowing you to really sink your weight into your heels, and opening up your hips. It may be helpful to ride the fences in a halfseat till you are more secure and able to follow the motion. In the second to last photo your def coming down to early.
You're eyes are up, and you have a nice high crest release in most of the photos. Your back is nice and flat as well. I think you have a good start and certainly your background has probably helped you adjust. Can you do me a favor and tighten up the chin strap on your helmet? It looks loose and will defeat the purpuse should you need it. Other than that, I'd say you did an excellent job of staying with a spirited horse for your second time jumping.