Fasting and abstaining are all a major part of Lent. Sometimes rules change and it is difficult to remember the guidelines for not eating meat on Fridays. You can never go wrong if you remember not to eat meat each Friday and offer more prayers to God.
In the United States, the U.S. Conference of Catholic Bishops has declared that "the age of fasting is from the completion of the eighteenth year to the beginning of the sixtieth."
The USCCB also allows the substitution of some other form of penance for abstinence on all of the Fridays of the year, except for those Fridays in Lent. Thus, the rules for fasting and abstinence in the United States are:
Every person 14 years of age or older must abstain from meat (and items made with meat) on Ash Wednesday, Good Friday, and all the Fridays of Lent.
Every person between the age of 18 and 59 (your 59th birthday begins your 60th year) must fast on Ash Wednesday and Good Friday.
Every person 14 years of age or older must abstain from meat on all other Fridays of the year, unless he or she substitutes some other form of penance for abstinence.
If you are outside the United States, you should check with the bishops' conference for your country.