As a freshman, I wouldn't recommend more than 35-50 over the winter, depending upon your previous experience. Whatever your mileage was for XC, gradually work up to doing 10% more than that.
Another freshman experience... My son is also a freshman and he averaged 35 mpw during XC. He is a pretty decent runner with a year of middle school experience (4:47 1600 PR). His coach is deliberately and conservatively increasing his mileage. He's almost back at 40 now (ten days off after state and slowly building mileage up again) and will likely be at 45 right before track starts. There's just no need for you to jump to 50-60+ miles right now (unless you have a history of running high miles prior to high school), no matter how much you think you have to gain from it. The risk isn't worth it.
Good luck! Hope you have a great season.