I agree with Jespah. But, my first advice is to immediately start streches.
Im a 17 yr old girl. And I am 5'4. I took gymnastics when i was around 8 or 9.
You took the class but for how long. The streches are more important then strength. Also, strech everything/ not just arms and legs. start with finger strech followed by wrist, elbow, shoulder, neck. I recommend doing one thing at a time one limb at a time. Choose an arm to start with, then switch each time you go to start the streches. Do slow rotations not quick movements, donot crack joints however let them crack themselves. Reapeat with feet, calves, hip and core. Core movements should be slow back and forth. Strech at least twice daily. When you wake up and before you sleep. Before excercise and after, every time! You should spend at least between 5 to 10 minutes each time. The streches I recommend are both relaxing and energizing. They more efficiantly improve streching, and you will be ready if you are telling truth of your strength. NOTE DISCLAIMER you are soully responsible for regimin, the one I reccommended is safe to preform and in most (if not all) people. If need further help ask. Also I don't mind a question that you personally would think is stupid.