If you said 6 months then it’s 6 months. I just went out with a girl whose profile read “ I want a man who is true to his word”. If you back down now then she will undoubtedly continue to test you. If you stay true to your word, even though she may not agree, she will respect you.
If she pushes you just say “sugar _______s, I love spending time with you, I adore you and enjoy what we have but I am just not ready to introduce you to my girls yet. I hope you understand. Make it clear that it isn’t about her it’s about what you feel is right for you and your girls.
