Command, precept, and example are all in favor of baptism following profession of faith as soon as possible.
The biblical account possesses a surprising consistency -- believers professed Christ and were then baptized, without lengthy delays.
 The day of Pentecost -- about 3000 gladly received the word and were baptized the same day (Acts 2:41)
 Following Pentecost -- people were being saved and added to the church daily (Acts 2:47)
 In Samaria -- when they believed, they were baptized (Acts 8:12)
 Eunuch of Ethiopia -- believed and was then baptized (Acts 8:36,37)
 Cornelius' gathering -- believed and were commanded to be baptized (Acts 10:44-48)
 Lydia -- heard the truth and was baptized (Acts 16:14,15)
 Philippian jailer -- baptized the very night he (and his family) believed; didn't even seem to wait until morning (Acts 16:31-33)
 The Corinthians -- were baptized when they believed (Acts 18:8)
 Twelve Ephesians -- heard the truth and were baptized (Acts 19:1-7)
 Paul -- seems to be a possible exception, but notice that on the road to Damascus there was evidently none who could baptize him and when the Lord sent Ananias to tell him what to do, he was immediately baptized (Acts 9:5,9,18).
One precept is identity. Baptism identifies us with Christ in His baptism and testifies that we are following Christ. This identification should not be delayed. Our obedience and identification prepare us to walk in newness of life. Raised out of a watery grave, we are pictorially raised to walk in newness of life (Romans 6:4). Death to sin, burial of the old man, and resurrection to new life are officially announced. A second precept is gospel order. The gospel order is -- received the word, baptized, added to the church, continuing in doctrine and fellowship, and breaking of bread (Acts 2:41,42). The Lord was adding to the Jerusalem church daily, such as should be saved; then they were baptized (or else not added to the church daily, since baptism precedes church membership), Acts 2:47. To preach the duty and necessity of church membership, the necessity of baptism to precede church membership, and then postpone baptism, is to deny in practice the truth we preach.
Baptism is a command of God to the convert (e.g. Acts 2:38; 10:48) and to the church (Matt. 28:18-20). Should obeying God be delayed? Is not a church guilty when it encourages sloth, even inadvertently, about obeying one of God's commands? How much more, possibly, this first command? Baptism is the first act of obedience required by God of the believer. Obedience should not be delayed. The evidence is heavily weighted in favor of baptisms sooner rather than later.
I understand some of the reasons raised in favor of delaying baptism. I also strenuously object to the easy-believism pseudo-evangelistic methods that are often associated with "quick" baptisms. Nevertheless, our reasons and objections are invalid in light of New Testament command, precept, and example.
The idea is not that if one professes faith at 11:55 a.m. that he or she must be in the water by 12:00 noon. The idea is that once one has professed faith, what scriptural hindrance is there between that and his/her baptism? The eunuch said, "What doth hinder me to be baptized?" How did Philip answer? "There are too many logistical problems, we'll have to put it off for awhile"? "Let's try to schedule it so Mom & Dad can be there"? or "After you've had a few classes on Baptist doctrine, I'll get back to you"? No! It was, "if thou believest with all thine heart, thou mayest." Philip could not baptize the eunuch until they arrived at the body of water, but when they were there, and there was a legitimate profession, there was NOTHING else that stood in the way of his baptism. If that's not a good Bible principle I don't think I'm capable of seeing one!
The order of the commission seems to be evangelism, then baptism, then instruction (Matt. 28:18-20). I am NOT saying that a person's baptism is not valid because it is delayed. I AM saying that our reason for delaying is not valid. This will succinctly sum up my position -- If a church accepts a person's profession as genuine, there is neither Biblical example nor doctrinal reason to delay baptizing that person.
"Christians, if your hearts are warm,
Ice and snow can do no harm;
If by Jesus you are prized,
Rise, believe and be baptized." - John Leland