Hello,
If you have never done the splits before, you need to be very careful. A good personal trainer can help you get those muscles nice and loosened up.......you can cause some major damage if you are not ready to try them. I was a gymnast when I was in my teens........and learned to do the splits then.....I can still do them, but at 46........I need to do ALOT of warm up before. One thing that really helps is a technique called "self myofacial release".......it helps prepare the inner thigh muscles to acheive that stretch. You should seek the help of a professional......a personal trainer or a gymnastics coach....someone well versed in the dynamics of muscle movement. Good luck and have fun.