The First Ammendemnt protects your right to not participate in reciting the pledge of allegiance:

In 2006, in the Florida case Frazier v. Alexandre, a federal district court in Florida ruled that a 1942 state law requiring students to stand and recite the Pledge of Allegiance violates the First and Fourteenth Amendments of the U.S. Constitution. As a result of that decision, a Florida school district was ordered to pay $32,500 to a student who chose not to say the pledge and was ridiculed and called "unpatriotic" by a teacher.

In 2009, a Montgomery County, Maryland, teacher berated and had school police remove a 13-year-old girl who refused to say the Pledge of Allegiance in the classroom. The student's mother, assisted by the American Civil Liberties Union of Maryland, sought and received an apology from the teacher, as state law and the school's student handbook both prohibit students from being forced to recite the Pledge. reference

You might suffer some immediate consequences from ignorant people, but courts have repeatedly upheld that this is protected by the First Amendment. Even the current Supreme Court would have a hard time justifying overturning this precedent.

You could even argue that choosing not to participate is a highly patriotic act, as an exercise of your Constitutional rights as a citizen.