Killed anyone? I have.... and not always because I had to for self protection.
Ever stolen anything? I have, several cars, money, and a few other things.
And, of course the list could go on and on. But the more important thing is that just because I became a Christian 38 years ago, some of those temptations still tugged at me. And not for just the first few months or years. They still come around even today. No, nowhere as strong..... but the point is that Satan still tries to get me to think I am not worthy of being anywhere around Jesus.
And, "Yes", over the years, I did still give in to some of those temptations, even though I was trying to follow Jesus.
One of the most frequent ploys Satin uses is to get you to think that because you have not convinced yourself that you are now totally sinless in your thoughts and actions....... and there actually are deluded individuals who will lie to your face (sinning, BTW) that they no longer sin, at all..... it is something the Bible tells us we will deal with as long as we still draw breath.
It all really DOES come down to deciding if you really CAN... and will.... and do.... trust that what Jesus says is true. That is the end thing you need to look at. It takes time. And some effort. Even a sensation of risking.
Really, there is not much more to this Christianity thing. Some do, some don't, you decide for yourself.