Beginning the Lenten Season, Ash Wednesday Masses will be offered at every parish. For special Mass times, please contact your local parish. Contact info and websites for each parish can be found here:
https://diocesetucson.org/parishfinder
From the USCCB: Ash Wednesday and Good Friday are obligatory days of fasting and abstinence for Catholics. In addition, Fridays during Lent are obligatory days of abstinence.
For members of the Latin Catholic Church, the norms on fasting are obligatory from age 18 until age 59. When fasting, a person is permitted to eat one full meal, as well as two smaller meals that together are not equal to a full meal. The norms concerning abstinence from meat are binding upon members of the Latin Catholic Church from age 14 onwards.