We abstain from meat in part because Jesus spilled his blood on a Friday and so we refrain from subjecting animals to the same sacrifice. In part, too, meat was traditionally a luxury, so as a sign of penitence we abstained from that luxury. Today meat is no longer such a luxury but it’s still part of our tradition. So we eat other foods – and you can be creative. Vegetarians survive quite well without beef, pork, and poultry! (And fish, other seafood, eggs and cheese are perfectly fine on Fridays so that gives a lot of flexibility. Tofu and peanut butter are OK too so protein really isn’t a problem)
There are only two fast days in the year – Ash Wednesday and Good Friday. And if you forgot, you forgot. Take steps so that you’ll remember in the future – mark Good Friday on your calendar now so that you’ll remember! If your parish gives away a calendar at the beginning of the year, take one. They usually put a fish symbol on the Fridays of Lent as a reminder and a different colored fish on Ash Wednesday and Good Friday.
The Catechism, starting with section 2041, gives the precepts of the Church. I think of these as the basic “rules” of the Church:
In summary:
- Attend Mass on Sundays and holy days of obligation.
- Confess your sins at least once a year.
- Receive the Eucharist at least once a year during the Easter season.
- Observe the days of fasting and abstinence.
- Help provide for the needs of the Church.
You can do more than follow these precepts – attend Mass more often, go to confession more often, etc. But these are the minimums. (And, of course, there are exceptions. If you’re sick then you should stay home from Mass and not worry that you’ve done something wrong.)