My nipples are swollen

Yes, it is quite normal. During puberty a boy’s body produces a surplus of the male hormone testosterone that helps a boy to develop into a man. This extra male hormone is converted to the female hormone estrogen that can cause your nipples to swell and be sensitive.
Normally this will disappear in the next two to four years although some men will lose the sensitivity but keep the shape of their chest that was formed during this process of becoming a man. See a doctor, if you want, but I don’t think you have to worry as some boys take longer to outgrow puberty than others.