The Constitutionality of Curfews

Many curfews contain 1st Amendment exemptions typically worded along these lines:

"Defenses: It is a defense to prosecution under subsection that the minor was:
[...] exercising First Amendment rights protected
by the United States Constitution, such as the free exercise of religion, freedom of speech, and the right of assembly."

(If there isn't an exemption specifically included, it should be implied, as the entire nation is governed by the Constitution.) Hence, is it possible that one could simply claim protection under the constitutional exemption if, for instance, they were wearing a sticker or button that said "I'm Protesting the Curfew" and argued that this was a valid exercise of their 1st Amendment rights?

Also, police officers are currently permitted to detain people if they have reasonable suspicion that they've committed a crime. (Hence their ability to detain youthful looking people for curfew violation.) Since police officers inetivably must ask the age of a suspected curfew violator, couldn't they claim that this violated their 4th or 5th Amendment rights against unreasonable search and self-incrimination? Stop and identify statutes that require a suspect reveal their name (and possibly address) have been ruled to be constitutional in Hiibel v. Sixth Judicial District Court of Nevada, but couldn't the requirement that a person reveal their age be ruled unconstitutional? I understand that some states and municipalities have exemptions that address this also.