When I was a kid all female teachers were “Miss” no matter their marital status and they had to take a leave of absence as soon as they started showing during their pregnancy. They just suddenly disappeared and when they came back they were still “Miss”. They were just our teachers. They didn’t have personal lives.
College students these days are pretty savvy and would no doubt accept who you are without giving it another thought, but in the end it’s what you’re comfortable with. There’s nothing in your contract that says you have to reveal anything about your personal life if you don’t want to.
Do what’s best for you. Your reluctance to share your life with them won’t have an impact on their learning. They’ll be fine.