Does the obligation to attend Mass begin after you have been baptized?
If you were baptized as a child do your parents have to bring you to Mass with them and after a certain age you must decide to go on your own?
[UPDATED, substantially revised, and corrected]
The short answer is that the obligation to attend Sunday Mass begins when children reach the age of reason, age seven at the earliest.
Children become subject to Canon Law as soon as they are baptized: Canon 96 of the Code of Canon Law [CIC] says,
By baptism one is incorporated into the Church of Christ and is constituted a person in it with the duties and rights which are proper to Christians in keeping with their condition, insofar as they are in ecclesiastical communion and unless a legitimately issued sanction stands in the way.
However, merely ecclesiastical laws do not bind until the subject reaches the age of reason:
Merely ecclesiastical laws bind those who have been baptized in the Catholic Church or received into it, possess the efficient use of reason, and, unless the law expressly provides otherwise, have completed seven years of age (Can. 11).
The obligation to attend Mass on Sundays and holy days is, in fact, an ecclesiastical law, found in Canon 1247:
On Sundays and other holy days of obligation, the faithful are obliged to participate in the Mass.
Therefore, insofar as the child’s obligation is concerned, it cannot begin until the subject is seven years of age, and never applies if he is does not have the use of reason (e.g., the severely mentally handicapped).
Having said that, children still have certain rights as baptized Catholics that parents have the obligation to respect.
For example, all the Christian faithful (including children) have a right to be educated in the Faith:
Since they are called by baptism to lead a life in keeping with the teaching of the gospel, the Christian faithful have the right to a Christian education by which they are to be instructed properly to strive for the maturity of the human person and at the same time to know and live the mystery of salvation. (Can. 217).
Moreover, parents have a duty to impart that education to their children:
Therefore, it is for Christian parents particularly to take care of the Christian education of their children according to the doctrine handed on by the Church (Can. 226).
Since, starting at age seven, children will be obliged to live out their faith by attending Mass, they should be already used to attending Mass before that obligation begins.
Therefore, parents do have leeway regarding whether to bring very young children to Mass—which can be logistically difficult—but the goal should be to bring them to Mass as soon as that is feasible.
(Naturally, the obligation to be at home with young children constitutes one of the “grave” causes that can excuse someone from going to Mass, along with illness, the obligation to take care of the ill, etc.)
Source: “Are there any guidelines from the Church regarding bringing children to Mass?” from Catholic Answers. (Thanks to svidgen for pointing this out.)