When she first planned on getting pregnant, she thought 3 months is a good time frame. But when she hit three months mark she felt she she just isn’t ready. She could not possibly predict how she’d feel if it’s her first pregnancy.
Even if she knew you were expecting three months mark, perhaps when time came she felt she’s not ready for it. There might be ton of reasons why a woman might need to wait longer to reveal pregnancy. It is not out of malice .
I do understand it’s not easy for you but you still have plenty of time to adjust with her help. Don’t distance yourself. It won’t resolve anything