Well, this is a tough one. First off, Stacy will not be the only woman in your life if things don't work out remember to keep a positive outlook.
She's Under Her Mother's Thumb
Second, Stacy is 23 you said. If she is 23 and she still is under mother's thumb there are bigger problems than the fact that she is a lesbian. She needs to work out her issues and become independent in order to be involved with you.
Families Will Always Influence Your Dating
No matter who you date, your families will always play a big part. You have to be able to accept their rejection and find a way to have common ground or your relationship will always be troubled.
I suggest you try to find a way to contact Stacy and make sure she is all right. Then I recommend you follow her lead, if she wants to end it because of the problems do so. If she wishes to continue, evaluate what you want. Remember, you have a long future ahead of you.