In the first place, no one knows whether this thief was baptized or not. The Bible does not say. However, we know one thing for sure about this thief, he lived before Jesus said, “He that believeth and is baptized shall be saved …” (Mark 16:16).
The thief on the cross had been dead fifty-three days before Peter preached, “Repent and be baptized for the remission of sins …” (Acts 2:38). A man cannot be held responsible for doing something which is not in effect while he lives. It took the death of Christ to bring the new law into being (Heb. 9:16-17).
Just remember that the thief on the cross lived and died under the law of Moses. We, on the other hand, live under the law of Christ (Gal. 6:2) which says, “He that believeth and is baptized shall be saved” (Mark 16:16). So, why try to be saved like the thief?
It turns out that Christianity is good for you and good for your kids. Well, I suppose if you have been listening to certain atheist it might not be obvious. Richard Dawkins, a well known atheist has claimed teaching children to accept their parent's religion is child abuse, and suggests it's even more damaging than sexual abuse. Interesting attention grabbing statement and completely wrong.
If you look at Christian families with unbiased eyes it is easy to see how beneficial practicing the Christian faith can be. If you need further proof, consider a 2018 Harvard study. Researchers kept track of over 5,000 youth over a decade. Their findings? Young people who went to church and prayed were more likely to say they were happy, more likely to volunteer, and less likely to use drugs. The study's author, Ying Chen, said "Many children are raised religiously, and our study shows that this can powerfully affect their healthy behavior, mental health, overall happiness, and well being."
We Christians don't need a study to tell us that but it's nice when someone from Harvard sees the truth.