In a child sex case involving a female victim, the trial court did not err by admitting 404(b) evidence in the form of testimony from another female child (E.S.) who recounted the defendant’s sexual activity with her. The evidence was relevant to show plan and intent. Because the defendant’s conduct with E.S. took place within the same time period as the charged offenses and with a young girl of similar age, it tends to make more probable the existence of a plan or intent to engage in sexual activity with young girls. Additionally, the defendant’s plan to engage in sexual activity with young girls was relevant to the charges being tried. Finally, there was no abuse of discretion under the Rule 403 balancing test. On the issue of similarity, the court focused on the fact both E.S. and the victim were the same age and that the defendant was an adult; there was no discussion of the similarity of the actual acts.