How much older was Joseph than Mary?

There is no teaching from Sacred Scripture or the Tradition of the Church that tells us the age difference with the Blessed Mother and St. Joseph. However, there has been a growing theological tendency among the saints and popes to see him as a young man, and thus probably about the normal age for a Jewish man to marry (late teens to 20 years of age). This would make him 5 or 6 years older.

Can you eat meat on St. Joseph Day?

Yes, when the Solemnity of St. Joseph, or any Solemnity, falls on a Friday of Lent, Catholics are excused from the law of fast and abstinence.