MY DEAR SISTER IN CHRIST,
This question of yours is one that Satan loves to use against the newly saved, playing with their minds trying to convince them that they are not "really serious" about the commiting their lives to our Lord Jesus, and are thus not saved, and therefore might as well give up and return to the world. DON'T FALL FOR THIS!
Not to oversimplify things--although it is pretty simple: If you look into your heart and see that you have a TRUE desire to COMPLETELY surrender yourself to our Lord--then it is a done deal. Our Lord accepts TRUE desires as accomplished facts--because, of course, He has foreknowledge of how it will all come out.
Learning to COMPLETELY surrender ALL areas of our lives to our Lord, God, and Savior is the work of a lifetime. Just don't lose your desire to accomplish this, and the Holy Spirit will guide and strengthen you step by step in this lifelong process. God looks for "PROGRESS, NOT PERFECTION", so just keep on keeping on as the Holy Spirit gives you light, and you will do just fine.
The best thing you can do right now is to find a Spiritual Mentor--pastor, youth group leader, elder, whatever--whose spiritual authority you can place yourself under so as to receive the mature guidance and support you need at the point in your walk with the Lord. DO NOT PUT THIS OFF, as Satan is alive and well and anxious to knock you off the straight and narrow path you have chosen. Also, if you haven't already done so, prepare yourself--with the help of your Spiritual Mentor--as quickly as possible for Baptism. This is most important in protecting yourself against the Evil One as the Holy Spirit's power is limited until Baptism allows Him to indwell us.
MAY GOD BLESS AND PROTECT YOU WITH HIS LOVE,
ephraim