She was 16, born Oct., I was 19, born Nov. So, 2 years and 11 months apart, would it be legal or not?

According to the law below, you would be violating 21.11 "Indecency with a child" if she is under 17 years of age. The fact that you are less than three years apart would only be an affirmative defense if she were of legal age to consent.

§ 21.11. INDECENCY WITH A CHILD. (a) A person commits an
offense if, with a child younger than 17 years and not the person's
spouse, whether the child is of the same or opposite sex, the
person:
(1) engages in sexual contact with the child or causes
the child to engage in sexual contact; or
(2) with intent to arouse or gratify the sexual desire
of any person:
(A) exposes the person's anus or any part of the
person's genitals, knowing the child is present; or
(B) causes the child to expose the child's anus
or any part of the child's genitals.
(b) It is an affirmative defense to prosecution under this
section that the actor:
(1) was not more than three years older than the victim
and of the opposite sex;
(2) did not use duress, force, or a threat against the
victim at the time of the offense; and
(3) at the time of the offense:
(A) was not required under Chapter 62, Code of
Criminal Procedure, to register for life as a sex offender;