In the past Bernard followed IKF standards which allowed 16 year old racers to run adult classes. I’d like to add in what I’ve seen through my personal experience related to time at the big tracks racing and watching. I also realize some runners at certain ages are more alert than others. Keeping in mind even a champion Jr sprint runner will come back eyes wide open after the first run at this speed without throwing in others around him or her. If your young runner has never ran 125 on the long track this may not be the event to test the waters. With this many people on the grid the dangers are extreme and can be amplified for a new person old or young. Your looking at 110+ mph in a large group, this is not the sprint track, again dangers are extreme. From 80 mph top end sprinting to sustained 110 for up to 30 seconds this is a big deal. Even Jr restricted 125 is going to be faster than most at that age need to be going IMO. Yes I know it’s not my place to judge your runner but please take serious consideration and or attempt to take your new person to a local long track event for testing before signing up. Some love it and some hate it, road race is definitely different.