Well, here is my opinion, for what it is worth. I also rode for years, not western and switched about 2 yrs ago. Bought a trail type horse who was , then decided I wanted to do reining. I cannot speak to how it is for everyone is in all areas, only in mine, and good trainers are NOT easy to come by. You have to be very careful, as I am sure you are aware. If you decide to stick with your horse, Yes, it will cost you plenty of $$. Reiners who are truly completive at least around here-really never do anything else. They stay at the trainers. When I sent my guy last fall, I knew I would be busy all winter so the timing was right. He also had the basics, similar to yours. I was told I could not ride him for a minimum of 60 days, which is about standard. It was recommended (and has been a HUGE help) that I take lessons on the trained horses so that I could learn what it feels like and how to ride one correctly. My guy has now been at the trainers about 6 months, I just got to ride him for the first time last week, and it is great....but he would not be ready for any rated competition for at least another year. Retraining takes longer. The plus, to using your guy is, as I see it, that you know him. You know he has not been used too hard at a young age, as many are. You can be fairly confident that he will stay sound for many years because of that. That said, I was also offered to purchase an older show horse to start my show career with My issue are several. I like to do other things. I do not want a horse that I can ONLY do reining on. I also like knowing that my guy was not started hard as a 2 yr old as many reiners are, at least here in the states. I am pretty sure that his hocks will not be spongy in short order.
From my experience here with my own horse, as well as my friends-same basic story, different trainer, to REALLY be competitive in reining you need to be totally dedicated to that. You also need to have pretty deep pockets, so that your horse can stay at the trainers a LONG period of time. People here in the states are generally not competitive unless their horses are. I will just go do fun shows, nothing big and be happy. If I decide to be really competitive, I will have to make the decision to spend minimum of $10K/yr just to keep the horse in training, far from me, so my riding would be minimal. I would rather enjoy my horse, who now has a really good "handle".
Most 11 yr olds will not last much longer if they have been and are going to continue to be campaigned heavily. If you decide to go that route, I would suggest FULL vetting prior to purchase, including extensive x-rays. JMHO.
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