In your situation, a lighter bullet and a muzzle brake goes well with the 280AI. You can still load a milder book load.
Both my granddaughters at ages 12 and 15 shoot mine (R700 280AI CUSTOM) with Barnes for a lead free junior hunt. They were using a 145 gr. weight LRX. They would all fall into normal height and weight categories. They love shooting this cartridge.
Second, if you search around, there may be reduced recoil 280 Remington ammo that may be shot in the SAAMI spec 280AI chamber (with the following article below from NRA's American Hunter):
"The primary difference between the standard .280 Rem. and the .280 Ackley Improved is the steeper 40 degree, which lengthens the case body and allows for about 5 percent more powder capacity. This sharper shoulder can also increase case life, which is a good thing for the handloader. In a pinch (read lost luggage), .280 Rem. ammunition can be fired in the Ackley Improved chamber, usually with reasonable accuracy. It is important to note that the SAAMI-spec .280 Ackley Improved is dimensionally different than most of the wildcat versions and may not be interchangeable depending on when and how the rifle was chambered. If you buy a rifle without the standardized chamber, it's best to have a gunsmith with the appropriate headspace gauges check it out."
Hope this eases your mind as there are options for you in your current rifle.