Many years of experience and much wisdom in the previous replies.
I can only add to this discussion what has been very helpful to me over the years, that is hunting small game. I was introduced to hunting small game with a longbow at around age six. Though I did have a few opportunities, I was not allowed to arrow a big game animal until age 12 when I killed my first whitetail deer. Though I was only 12, by that time I had a bunch of string time under my belt arrowing several species of small game. No matter how much string time you have in the comfort of a familiar course, and no matter how well you can string together a succession of well placed shots on an inanimate target, I cannot begin to stress enough the difference in felt pressure of making the one shot you may take on a live game animal when afoot in the woods during conditions that are often far less then ideal. There have been volumes of books written on this very subject in the world of hunting archery of which at times can prove to be a huge stumbling block for some to overcome. I have found very few things in archery that can duplicate this experience any better than spending time afoot in the woods hunting small game. Such time spent will quickly help you to develop your woodsmanship and tackle management skills when hunting with your longbow. Such time spent will quickly help you to develop stress inoculation against game panic when you decide to take that first shot on a live big game animal. Such time spent will quickly help you to develop your confidence in your abilities to accurately place a killing shot with that first arrow while hunting during conditions that are often far less then ideal.
So my suggestion would be that you broaden your horizons by not becoming a single dimensional hunter who only goes after a narrow range of big game animals that you only shoot from a stationary shooting box within a limited duration of time each year. Expand your horizons as there are numerous opportunities to enjoy your longbow afield throughout the entire calendar year while going after a plethora of fish, fowl, small game, big game, dangerous game, and vermin. Also, if you find yourself in the back country on a hunting trip with friends on a non-hunting day, you can easily lay out an archery golf course with minimal materials gathered afield and spend a great day practicing all sorts of shots over a game of archery golf:) Also, you can hone your low light shooting skills by spending time each evening shooting at small candles around the campfire. The list goes on and on, and all will improve your hunting skills over time.
Best,
DB