Especially since the vows changed in the mid 80's, baptism among Jehovah's Witnesses is considered an outward symbol of an internal event, dedicating one's life to God Jehovah.
In reality Witness baptism is a declaration of intentions, a social contract that is unbreakable, and is encouraged for those who are too young to enter into any other legal contract. The majority of most baptized now are under 18, the legal age in the US.
The record of your contract with the organization is kept forever, on paper, with the local congregation and with the worldwide headquarters of Jehovah's Witnesses.
It is a rite of passage for all witnesses; without baptism, you are not part of the community and are regarded skeptically. If you are not baptized and seek a marriage mate, you are considered to be an unbeliever until you are baptized.
There is no social advancement or ‘privileges’ of service given until baptism.
This is the problem for young witnesses, even preteen witnesses; you must be baptized to fit in, and to please your parents, but baptism means that you have chosen to be a Witness for life before you ever can get perspective on who they are or what they teach. (Interestingly, the Society discourages other major decisions, such as marriage, until one is much older.)
The punishing social nature of Witness baptism should be illegal, or at the very least the reality of what baptism will bring should be provided for those who consider it.
From baptism on, regardless of age, one can be removed from the community of Jehovah's Witnesses for perceived or real mistakes or for attitude, with no recourse in a real court of law. The decision about your mistakes will be made by those who know you, and may or may not be biased against you.
Even worse, it can be announced that you have removed yourself if they find that or decide that you have taken blood or voted.
Witness baptism has nothing to do with faith, an internal process, and everything to do with social acceptance, peer pressure and legality.