They just don’t think it’s that serious, and if I bring up going by myself, or getting a ride with someone else, I know they’re just going to talk about how I’m overreacting. On Sundays where they don’t drive to church, I feel guilty for the rest of the day, and go back and forth about whether or not I committed a mortal sin.
Hi Tennis,
First, I would show them this from the CCC:
The Sunday obligation
2180 The precept of the Church specifies the law of the Lord more precisely: "On Sundays and other holy days of obligation the faithful are bound to participate in the Mass."117 "The precept of participating in the Mass is satisfied by assistance at a Mass which is celebrated anywhere in a Catholic rite either on the holy day or on the evening of the preceding day."118
2181 The Sunday Eucharist is the foundation and confirmation of all Christian practice. For this reason the faithful are obliged to participate in the Eucharist on days of obligation, unless excused for a serious reason (for example, illness, the care of infants) or dispensed by their own pastor.119 **Those who deliberately fail in this obligation commit a grave sin. **
2182 Participation in the communal celebration of the Sunday Eucharist is a testimony of belonging and of being faithful to Christ and to his Church. The faithful give witness by this to their communion in faith and charity. Together they testify to God’s holiness and their hope of salvation. They strengthen one another under the guidance of the Holy Spirit.
2183 "If because of lack of a sacred minister or for other grave cause participation in the celebration of the Eucharist is impossible, it is specially recommended that the faithful take part in the Liturgy of the Word if it is celebrated in the parish church or in another sacred place according to the prescriptions of the diocesan bishop, or engage in prayer for an appropriate amount of time personally or in a family or, as occasion offers, in groups of families."120
This should help show them that it is a big deal to miss Mass although not really for you as you have a desire to go to Mass but are not being let to do so. This is not your fault because you are honoring your parents wishes.
Secondly, I would continue to ask them every week without fail if they will go to Mass or let you ride your bike to Mass. Be very consistent in this because it will show them you are very serious about going to Mass. Obey their deciscion but continue to ask. Be respectful but** very sincere **about it though.
Thirdly, If they continue to refuse to let you go to Mass or ride your bike on days they want to skip it, ask them if you can have the Eucharist brought to you. I don’t know if their is a precedent for this, other than communion to the sick, but again this would show how serious you are about going to Mass. Contact your priest and explained your situation, I am curious what he would say. Or does anyone know if this is out of line.
I think this would serve three functions. Firstly, what possibly good reason could they give for you not receiving the Eucharist in your home other than their own embarassement or thinking it is unreasonable. YOu are not biking anywhere and you are obeying them when they say they are not going to church that day. Secondly, again this shows you being consistent in how much your sunday obligation means to you. Thirdly, It wouldn’t hurt to have your parents witness you take communion, even at your own home, and be exposed to the Blessed Sacrament in their home personally. It might even help the feel the tug of Jesus more fully.
Of course, you must obey your parents until you are old enough to go to Mass on your own. If they deny all these things, continue to read the bible, at least some every day and match up your reading with what is being read in Church on that Sunday so at the very least you are exposed to the liturgy of the word. Also, I would continue to read more about your faith as well as this will help you stay catechised until you can return to Mass. Just search something on the “read” section of
Catholic.com and learn something new about the Church and Catholicism every week.
Hope this helps. Keep up the good fight and good luck.
Remember, at least until you are at an age where you can make up your own mind: 
