3. On the topic of apologizing or making restitution ”“ if you have received Jesus and He dwells in you, allow Him to guide you in those decisions.
My personal opinion (and I should stress, it is only an opinion):
(i) It's not realistically possible to make restitution for every sin or lie you committed in the past ”“ e.g. you cannot make restitution for the candy you stole 50 years ago, or the lie you told to a stranger 10 years ago.
Keep in mind that we are kept saved by the blood of Jesus, not by our attempts at apologizing or making restitution. As William Tyndale reminded his readers, "It is faith in Christ’s blood is counted rightÂeousness and a purging of all sin before God."
(ii) If you feel that apology or restitution for a particular sin is within your capacity (especially if it is important to the aggrieved party), then that should be something that you prayerfully consider with God.
To be honest, you can never make full restitution for a past sin (the wronged party would have gone through physical, emotional and mental duress as well ”“ these are things you cannot compensate for). But sometimes just an acknowledgement of wrongdoing and an apology is meaningful enough to the wronged party, and that might suffice.
4. As a born again Christian, of course you should stop your habitual sins ”“ and that's in fact what you truly want, i.e. your new heart (given by God, c.f. Ezekiel 36:26-27) does not want to sin.
To live aligned with your new creation identity and new heart ”“ that's called "walking in the Spirit". I think Andrew Farley has some good material on that (look up his Youtube clips); I've found "Lifetime Guarantee" (Bill Gillham) to be pretty useful as well.
It's all about learning how to live under God's love and unmerited favour for you. There's definitely a growth process to that. But your growth can be quicker if you develop a proper understanding of the gospel, and thus know how to rightfully renew your mind (Romans 12:2).
May you know of God's delight in you, and that He has utterly saved you (Hebrews 10:10, Hebrews 7:25). God bless your Christian journey with Him.