School back in, but you're still not out? Telling your classmates and friends you are gay is one thing; should you come out to your teacher as well?
Coming out is a selfish act, as it should be. It's not about other people; coming out lets you be your genuine self. This means that you are free to tell as many or as few people as you like. There is no magic number of people you have to come out to be be "out." Your entire school, including teachers and staff don't have to know about your sexuality. You are allowed to maintain the same level of privacy as other students.
So, telling your teacher or professor about your sexuality is an individual decision. Still, think about why you want to tell them? Are you looking for support? They may be a good place to turn. They have a professional obligation to help or direct you to the right places, but keep in mind that you can't be sure about their personal feelings about LGBT people.
If you want to tell them, feel them out first. You can let them know that there is something personal that you'd like to discuss. Consider having a close friend with you. A teacher that's willing to help will ask how they can help you adjust to the school environment. Think about ways they can help you either come out or be out on campus.