Hot water pressure is low hot water comes and goes the electric heater is 27 yrs old cold water pressure is fine

Let me see you have a hot water heater that is 27 years old. That is just unheard of, most likely that is where the issue is, question do you have good water pressure before the heater ? Then test the pressure out of the heater

Hot water pressure is low. Hot water is coming and going. Electric water heater is 27 yrs old and we have well water. What can we do?