Hey man, going after those nationals is a really cool goal. Focus on the weight loss and mileage over the next year. That'll make the biggest difference. I'd check if there are any local gravel groups or lower key races before then where you can get experience without as much pressure. Most of all, have fun with the training. Don't sweat losing at nationals if it happens, just enjoy being there, That's it. I won't be personally so competitive, though.