Direct answer
Becoming a Christian is not a ritual. It is turning from sin (repentance) and trusting Jesus Christ (faith). If today you honestly ask Jesus for mercy and rest on Him alone for salvation, He will not turn you away (John 6:37).
The New Testament calls people again and again to repent and believe. Repentance is a change of mind and direction — away from self-rule, toward God. Faith is trusting Jesus with your whole life. Both are gifts of God's grace at work in you.
Related passages
Acts 2:38 · Romans 10:9–10 · John 6:37