Yes, nightfall can generally be a normal physical occurrence at age 18. During puberty and adolescence, wet dreams/nightfalls are common, along with hormonal changes and sexual development.
There's no set "normal frequency" for nightfall. Some people may experience them occasionally, others more or less frequently. It's not correct to assume that nightfall alone indicates weakness, infertility, or a decrease in sexual potency.
If nightfall is accompanied by symptoms such as pain, burning during urination, blood in the semen, or strange discharge, or if this problem bothers you frequently, it's advisable to consult a doctor.
Otherwise, there's generally no need to worry. Adequate sleep, regular physical activity, a balanced diet, and stress management are all helpful for overall sexual health.
