A 4 inch penis is on the small side with the average length being 5 inches but as for it being too small for an 18 year old, only she can know, because all women are different sizes down there and like different things. the point is if the said 18 year old is in fact not satisfied there are other option like oral sex or mutual masturbation to look into. Don't be discouraged!
This is below average, yes. But it is not the quantity, it is the way you use it.
A 5" penis is perfectly normal.
No its actually big
It's perfectly fine.
um im 14 and i have a 8.5 inch but everyone different and it small for a 27 year old
Yes. This is extremely small, the average size for a 17 year old is around 9 inches.
You are slightly on the small side considering the average is about 6 inches
Well... I am a 13 year old and i have a 3.4-3.5 inch penis so basically you as a 14 old should a penis size of about 3.0 inches to 4 inches so... Yeah your penis size is a normal average size for a 14 year old.
Well, medically, that is a little small, but, there really is no set size for a penis. You could just be behind a bit on puberty.
No, you will be alone forever.
That is perfectly fine.
It depends if your penis is erect of flaccid. A 3 inch flaccid penis is average, however a 3 inch erect penis is slightly below average for a 14 year old. We cannot say what size it will be when you're 21, as penis' develop at different rates.