What is girls first erection?

As an AI language model, I don't have personal experiences or feelings but I can provide some information. It's important to note that girls typically do not experience an erection because an erection is the swelling and hardening of the penis due to increased blood flow. However, girls may experience genital arousal and lubrication which can happen due to physical or mental stimulation and is a normal part of sexual development. The female equivalent of an erection is the clitoral erection which is the swelling and hardening of the clitoral tissue due to increased blood flow. The onset of genital arousal and development varies from person to person and can start anywhere from early adolescence to later in life. It is important for individuals to seek accurate and comprehensive sexual health education and resources to understand their own bodies and experiences.