Thanks for your brave post. I really hope you will stick around this site. I stuck around, and I have this site's guidance to thank, in significant part, for the meaning I have found in my own life.
Because your mother is Jewish, you were born with automatic access to a treasure-house of literally the best things in the world. I am talking about a history of holiness, a durable commitment to G-d across long time and space that is absolutely unprecedented and unmatched in human history. About a code of law that stitches life and lives together with methodicalness and seriousness, with memory and with light. About tradition, yes -- and also about a present in which Jews flourish in their Land and in the world, building it up and making it holy and imbuing it with righteousness and kindness and genius in a way quite unexpected -- and about a future in which we envision, expect, and pray that these good things will have filled the world to the exclusion of all evil. And you are part of all this. Indeed, you are the whole.
It is an incalculable privilege, and one which our people has paid dearly to safeguard and pass along to you. You are sixteen, which means you have your whole adult life ahead of you. You can choose, now, essentially any path in which to invest the energy of your future, and it is likely that you will live to see the results. Decisions made at age sixteen do not always persist, but if they are of a certain kind, they may.
Sixteen is a very good time to start learning Torah. Learning Torah is the life's work of a Jew, and the earlier you start, the easier it is to do well. I would recommend finding your nearest Chabad House using this link and stopping by, either on Shabbos or during the week, to talk to the rabbi. If the rabbi isn't there, go back later. If you don't like the rabbi, try a different Chabad House. Tell them you are serious about learning and would like to make up for lost time and go further. Bring your siblings if you can convince them -- and your parents, too, if you like. And then, don't stop there: go back as often as you can, and see where it takes you.
As you start keeping Shabbos, you'll find yourself with an amazing thing: time to read. And so read these two books: The Thinking Jewish Teenager's Guide to Life and This Is My G-d. Both are far more readable and interesting than what I have just written.
You are very lucky to be thinking of these questions now instead of later, because you have the rare chance to get it right the first time, rather than desperately try to revise things at midlife or, like almost everyone, during your last days on Earth. If you approach Judaism with love and happiness and pleasure and meaning, it can fill your whole life with happiness and pleasure and love and meaning -- and also deep coherence -- in a way that few things can. It is not easy or straightforward. But even the mistakes and wrong turns and failures will be permeated with a subtle but unmistakable light if they were reached through an honest attempt to live for G-d.
The Almighty should always help and be kind to you in your search for good life.