57f, Me 46m. My girlfriend is too tight. What do I do?

Probably the weirdest post I’ve done or read about. My girlfriend, 56f, me 46m, hasn’t had sex in 10 years. We’ve been together a little over 3 months. So when we attempted to she was too tight and it didn’t work. I am in no way super large by any means. So my question is, anyone ever had experience with this? If so, please help. Thanks.