Yes, a statement from a witness alone is enough to charge and try someone of a sex crime. The statute of limitations for a sexual assault of a child in the State of Texas committed eight years ago is 10 years after the 18th birthday of the victim, so charges brought at this time could go forward on that basis. The State takes these accusations very seriously and will likely argue that there are good reasons why the accusation is credible. They will say that her credibility is bolstered by giving a statement that is consistent with her previous statement given at age 5. Hundreds if not thousands of Texans have been convicted of this type of crime based only upon statements given by the alleged victim.
You need to contact a criminal defense attorney who has experience handling sexual assault cases ASAP.
A person can be charged with a crime if there is probable cause. A person's ("victim's) complaint is enough to charge somebody. Whether that will be enough to convict the accused is a different story, but old statements matching the current statements do not bode well for showing that this girl is lying. They don't need physical evidence (semen, torn hymen, etc.) for a conviction.