I have started 5 colts in the past. It's totally your choice, if you're not sure you want to it's probably better to send yours out to get started. Just be sure that you get to watch the trainer working with your horse regularly, and that you're happy with the progress. I've seen many people who aren't really happy with how their horse is being handled but figure they shouldn't say anything because the horse trainer knows what they are doing. There are many people out there who call themselves trainers but really don't know what they are doing. If you're uncomfortable with how your horse is being handled or don't think he's progressing, ask the trainer what they are doing and why, and make sure you understand and are happy with the answer. That said, there are also a lot of awesome trainers out there too! Hope your colt is doing well.