Repentance Old and New Testament

When Israel was a child, I loved him, and out of Egypt I called my son. But the more I called to him, the farther he moved from me, offering sacrifices to the images of Baal and burning incense to idols. (Hosea 11:1-2 NLT)

So Paul, standing before the council, addressed them as follows: "Men of Athens, I notice that you are very religious in every way, for as I was walking along I saw your many shrines. And one of your altars had this inscription on it: 'To an Unknown God.' This God, whom you worship without knowing, is the one I'm telling you about. (Acts 17:22-23 NLT)

True repentance turns one toward Christ.
True repentance changed one's mind about Christ.

The Hebrew word for repent in the Old Testament is שׁוּב, which mean "to turn back, return".
The Greek words for repent in the New Testament are μετανοέω and μεταμεληθεὶς which mean "I change my mind".

Israelites are like second generation Christians. They know God but refused to follow Him. To repent is to return to God and follow Him.
Gentiles are like first generation Christians. They know nothing about the true God. Their ideas of god or gods came from their parents, religion and culture. When they find out about the true God, they change their mind about God and follow Him.

Now repent of your sins and turn to God, so that your sins may be wiped away. (Acts 3:19 NLT)