Pursuant to Texas Penal Code § 22.011 and § 21.11, the age of consent in Texas is 17. So, it is not a defense to these charges that a minor gave actual consent.
The age of consent is the age at which an individual may legally consent to engage in sexual activity with another person. Similarly, Texas Penal Code 21.11 (Indecency with a Child) prohibits sexual conduct with a child younger than the age of 17. In Texas, once a person has turned 17, the law presumes they are able to give consent. There are other situations in which a person that is 17 or older legally cannot give consent.
Also, if the victim for any reason is physically unable to resist or appreciate the nature of the act being performed, there is a lack of consent.
Consent is lacking in any situation where the defendant is in a place of power or charged with the care of the victim.
Under Texas law, with very limited exceptions, it is illegal to have sex with a person under the age of 17.