Hi Jennie
First and foremost Let us talk about the verse you are referring to when you state "everyone pray to be counted worthy". I believe you are referring to Luke 21:36 "Watch ye therefore, and pray always, that ye may be accounted worthy to escape all these things that shall come to pass, and to stand before the Son of man". Jesus is talking to the apostles about the end of the age and the beginning of the Kingdom of God.He is not talking about the rapture, He is talking about the second coming.He is describing what will be going on during the great tribultion period when the Church will be gone. During that time the believers  will be led to Christ by the two witnesses and the 144,000 sealed Jews. One of the main messages is not to take the Mark of the Beast. It is important to "overcome and be counted as worthy" during this period because it is no longer the Gospel of Grace because it you do not overcome and you take the mark of the beast you will then NOT been counted as worthy.
 
The part of the Bible written mainly to the Church Age would be Romans all the way through Philemon. Jesus taught Paul himself about the mystery being the Church. This mystery was not revealed in the Gospels for the apostles to understand. They did not understand the resurrection until it happened. If you disagree with this then tell me why they were not looking for him to rise from the grave?? Anyway, Paul teaches very clearly we are saved and by no means are we accounted worthy by any of our own deeds. The only reason we go in the rapture is because of our faith in Jesus EVEN if we are not "looking". There is a reward for the "watchers" but the rapture is a reward for the entire Bride the church. Jesus is not going to leave a hand or a foot or arm on this earth He is taking the whole Body of Christ.
 
Read I Thess chapter 5. He is talking about the rapture. I just want to point out a few verses. You can pull it up and read the rest.
Notice verse 6 says "therefore let us not sleep as do others; but let us watch and be sober" Paul is telling us not to sleep but watch. Now look at verse 9 For God has not appointed us to wrath, but to obtain salvation, by our Lord Jesus Christ" You may say to me YES he is talking about the "watchers" or the ones awake or whatever but look at verse 10 "Who died for us, that,whether we wake or sleep, we should live together with him. YES even the sleepers as counted worthy. Now you may say he is talking about the dead in Christ here but in context going back to verse 6 he is talking about the people who are asleep or not watching.
One more thing
look at verse 23-24 of I Thess quote from NIV. "May God himself, the God of peace, sanctify you through and through. May your whole spirit, soul and body be kept blameless at the coming of our Lord Jesus Christ". verse 24 "THE ONE WHO CALLS YOU IS FAITHFUL AND HE WILL DO IT".
 
Yes Jesus will keep us sanctified through the Holy Spirit. Our old sin nature will be "left behind" at the rapture.
 
You know that all of our righteousness are filthy rags so how can we do anything in the flesh to please God.
 
Please answer me this question. Will only some of the dead in Christ rise at the time of the rapture?
 
thanks and I hope you understand this.
Mike W