You are free to follow your conscience in seeking to follow God, however He leads you, but it may be prudent to wait until you are 18.
While you are clearly old enough to make up your own mind, you do have to live with your parents. If you had an adult that was your sponsor that your parents knew and trusted, it might make things go quicker, but don't rush.
Being respectful of your parents is also a commandment, so do everything you can to honor and love your mom and hopefully she will come around. If she doesn't, you can move forward as your conscience leads.