My opinion of what consitutes "good" physical shape for I-day (women):
*Pushups: 38
*Flutterkicks: 75 4-count in boots (without stopping)
*Run - 4 miles (without stopping) at about an 8:30/mile pace
*Pullups - 3
"Good" is above average. Hit or exceed that, and you'll be just fine. Your cadre will be in much better shape, and have the benefit of being used to the altitude. Some basics will inprocess hardly able to do 20 pushups. They will have a rough time with the physical aspect, which tends to take a mental toll.
Regardless of initial condition, you WILL improve in BCT...via organized hour-long workouts in the morning (alternating calisthenics and running days), cadre-led workouts throughout the day, and intramurals about every other evening. In Jack's Valley you'll be engaged in some sort of physical activity for most of the day.
If you are playing a sport, keep it up and add more of whatever you are weak in (running, upper-body, etc). Really work on cardio, because the altitude can hit you like a sledgehammer. If you aren't in-season or don't know where to begin, a mainly body-weight workout system like P90X or Insanity will increase your strength and overall fitness.