In that case, re-examine pros and cons of your choice then have a heart to heart talk with your mother. Go with an open mind not a confrontational mindset. Tell her your wishes and ask her about her concerns. Tell her how much you value her guidance but why it’s important for you to make your own decisions now as you are old enough and like any mortal, have only one life to live. You two should be able to find a mutually acceptable solution.