What's the alternative? To stay in the closet and be miserable for the rest of your life?
How well do you think you can serve your children by living in a false version of who you are?
A happy parent is the best parent.
My coaching program, The Talk Made Easy, helps Christian moms talk to their daughters about sex, values and relationships. Every single client I have worked with in that program had to confront who they are as a person, deal with their own hang ups before they could show up powerfully for their children.
Your children become who you SHOW them, not what you TELL them.
Will they have TONS of questions? Yes.
Depending on the beliefs you raised them on surrounding the LBTQIA+ community they might be confused. If you were very much against homosexuality and now you are saying you're gay, ANYBODY will have questions.
So, what do you do? You first believe it is okay and even better for the well-being of your children that you be 100% authentically YOURSELF. If they have questions, answer them honestly and thoroughly---and age-appropriately.
Often parents find that younger children are much less likely to be intolerant & confused about same gender relationships as older adult children. They haven't had time to form negative or positive opinions. They simply accept you for who you say you are.
How they respond will depend on how good or bad of a job you've done raising them to accept all people. But no matter what, you can build a healthy relationship with your child and make a course direction at ANY time.