Your normal Friday penance is lifted because on a solemnity there is no fasting or abstinence!
GENERAL NORMS FOR THE LITURGICAL YEARChapter 1, Title 1, Section III
12. The celebration of the two greatest Solemnities, Easter and the Nativity, is extended over eight days. Each Octave is governed by its own rules.
1983 Code of Canon Law (currently in force)
Can 1250 The penitential days and times in the universal Church are every Friday of the whole year and the season of Lent.
Can 1251 Abstinence from meat, or from some other food as determined by the Episcopal Conference, is to be observed on all Fridays, unless a solemnity should fall on a Friday. Abstinence and fasting are to be observed on Ash Wednesday and Good Friday.
Can 1252 The law of abstinence binds those who have completed their fourteenth year. The law of fasting binds those who have attained their majority, until the beginning of their sixtieth year. Pastors of souls and parents are to ensure that even those who by reason of their age are not bound by the law of fasting and abstinence, are taught the true meaning of penance.