Is it bad to go from lazy to super active in a short period of time?

You should be fine: You are young, so I don't feel that you are at risk from suddenly becoming very active. However, you might notice muscle soreness and fatigue if you exercise too hard. Make sure to drink plenty of fluids, stretch after exercising, and if you feel dizzy or weak, stop and rest. Listen to your body.

Take it slow.: It would not be wise to embark on an intensive exercise regimen right from being sedentary. You will be able to tolerate such an intense regimen in the future, but you have to build up your strength and endurance slowly. Start with light weight-training and short cardio sessions, for example, and add weight and time as your tolerance builds.