Salvation means freedom from sin and its consequences, believed by Christians to be brought about by faith in Christ.
It obvious that many don't know whether they are born again or not. There are certain thing we need to understand about salvation.
Salvation is a process that occur within you, God start first with your spirit man, reason because God knew your spirit before you mortal body. (John 17:24).
It is a process that your spirit is going through and as such you don't have to loss hope that you are not yet save in Christ.
Scripture says that " as many that received (John 1:12). All what God expect from you is just to receive his son and believe in him.
With my little experience in secondary school outreaches, I encountered some of this questions
- why is this happening to me, do i really confess Christ as my lord and savior?
YES, I answered, God start saving you from your within so that your spirit can align with the spirit of God. From then, the fruit of the spirit begins to manifest in you which will shape you physical live.
He ask again why, am I still sinning?
You don't expect the first day you gave you life to Christ, immediately your life get transform to be like God. God is preparing you to be like him.
You can be influence by your peers or your friends.
You can also be influence by your environment.
THINGS YOU NEED TO KNOW
1 Once you confess christ, you become a new creature
2 The working of your salvation is a part you need to do it by yourself.
HOW?
By Constance fellowship with God.
By joining Godly group like 
By reading spiritual books
By Constance prayer and studying the word of God