One thing to remember is the young age of this horse. His teeth are still growing, and changing constantly so any bit will need to be measured very carefully and changed frequently as his mouth changes. Personally I think he is far too young for a bit, but it's up to you, just keep checking the size, width and height etc, make sure his tongue has enough room and no pinches as it won't sit properly on the bars just yet if you do get one, or you may damage his mouth and put him off bits for life.