Assuming you're in high school, especially if you just started running, it's hard to predict a mile time based on a 400. When I was a freshman (age 14), I ran a 59 and 5:02 (mile not 1600). When I was a senior, I ran 55 on a relay, 2:01 and 4:25. Now I am 44 and would run around 65 and 4:45. Just keep running daily over the summers and between seasons, and you'll improve.