TexasCHLforum.com

(ii) if the individual possessing the firearm is licensed to do so by the
State in which the school zone is located or a political subdivision of the State,
and the law of the State or political subdivision requires that, before an
individual obtains such a license, the law enforcement authorities of the State or
political subdivision verify that the individual is qualified under law to receive
the license;

It does not say you must have a license from the state you live in, but the state the school zone in located. Therefore, if you drive by a school in another state that accepts your Texas license you're not covered unless you have a license from the state you're visiting.

Good thing they don't check this all the time.

Mike