You may become Catholic and receive all of your sacraments at any age, though since you are a minor, you'll either need to get your parent's permission or wait until you are eighteen. Meanwhile, you may want to do some study; there is a book called the YouCat (Youth Catechism) that may be helpful.
To start the process of being received into the Church, simply locate the nearest Catholic parish, masstimes.org will help you, and contact the priest for a meeting. You don't need to ask anyone's permission to start going to Mass on a regular basis (though having someone to explain it or guide you would help).
Another book you may find helpful is Bishop Robert Barron's Catholicism: A Journey To The Heart of the Faith.
May God bless your journey!