I don't believe that Judas knew that they were going to kill Jesus because when he found out, he tried to bring the money back and told them Jesus was innocent. But they didn't care. They finally had what they wanted and there was no way they were going to let anyone deny them the joy of killing Jesus. Judas tried to make things right, but it was too late.
When we decide to do or say something, we should think about it first. In a lot of cases we find out that when we really think about something, we often change our minds. There may come a time in your life, if you're not careful, when it will be too late to make things right with Jesus. The bible tells us that now is the accepted time, now is the day of salvation.
Don't put things off until tomorrow. Tomorrow may never come. We only have today. If you haven't done so already, accept Jesus into your heart. Maybe you find you have slipped away a little. If you have, ask Him to restore you and your relationship with Him. If Judas had asked Jesus to forgive him, He would have. He will forgive you too. Just ask Him.