I suggest you work your weekly mileage up gradually, young man. Maybe 20, 20, 25, 20, 30, 25, 30, 35, 30, 35, 40, 35, 40 or something like that. I like the stairstep method of increasing weekly mileage. You have many years of running enjoyment ahead of you so savor the process of slowling improving and getting better and better over the next 20 years or so. I hit my pr's in the mil3, 5k, 10k, half, and marathon when I was 37 and began running at 27. It is a gradual process and needs to be enjoyed. Life is a one way trip. enjoy the ride!
Your cc coach will be glad to see you on the team!