Is it obligatory for an unmarried girl to perform ghusl if she feels wetness and a brief sensation in her genital area during sleep without reaching the stage of climax or ejaculation?

A ghusl (ritual bath) is obligatory for someone who experiences a wet dream if they see semen, without exception. If you find wetness after waking up, and it is semen with its specific characteristics, then ghusl is obligatory. If it is pre-seminal fluid (madhiy), then istinja (washing the private parts) and purifying the body and clothes are obligatory. If you are unsure whether it is semen or pre-seminal fluid, ghusl is not obligatory; rather, you have the choice to follow the ruling for semen or pre-seminal fluid. This is the well-known position in the Shafi'i school of thought.