3 months is a fgood amount of time to get more flexible. Make sure you really get a good warm-up to get the blood flowing through the body to allow the muscles and tendon to get warm. This allows the muscles and tendon to stretch better. For best results quciker is to stretch after you warm-up and stretch after you practice since you body is warmer.

To get a good scorpian, you will need to have a split, back bend, and shoulder flexibilty. Based on what you explained, it sounds like you quardriceps and the hip flexort muscles are tight and cuases it not to hyperextend back to get the leg up for the scorpian.

This is what you can do with a partner. First lay on your stomach and bend your left knee. Have you partner place the hands on your lower back (to keep the hip on the floor) and the other on your knee. You partner will lift the leg back gently till you feel a gentle pull. Hold for 15-20 seconds and repeat 3 times.

You can also have you partner stretch you scorpian for you while standing up. Again hold the stretch for 10-20 seconds and repeat 3 times.

Good luck!