That is wonderful!
Hmm, my old horse, Lexi, used to be a Western horse. Last year, I had switched to English, & she did well at first- but not all horses can manage the transition (in a lot of cases they can, but not all horses)- for example, I was going to do some jumping with her. She wasn't really good at the jumping, & she really showed herself off with the barrels (I didn't show barrels, but she was very good with them). :) I didn't want her to be forced to jump or anything. I tried training & all that, but she just wasn't gripping it. & that was okay; because down the road, now she's with someone who does her favorite thing: BARRELS! :) & it really worked out for the both of us.
But anyway; I think your horse will be fine. Take things gradually, as it does take some time for horses to get used to change. Good luck!