4 month old water heater

I have a state 30 gallon low boy, I just replaced it around 4 months ago. It is set at 120F. It seems that after I take a shower usually around 5-8 minutes, it takes a long time for the water to get hot again coming out the faucet or tub. I don't think I am using that many gallons of water in my shower as the hot water usually runs about have strength. Does anyone have a clue to what could be causing this. Some other info I have a well, my tank is in the attic, I have a 1 1/2 story home about 1288 tsqf. Thanks

Some of those WH's use 120vac, which is limited in how fast it can reheat the water. Is yours wired with 120 or 240vac.

A typical showerhead uses a bit over 2gpm and not more than 2.5 (by federal regulation). If yours is really old, it could use quite a bit more (or if you took the restrictor out).

Ensure it is plumbed properly - that the hot is going in the hot side. If they're swapped, you'd be drawing water out of the bottom of the tank which is where the coldest water is.

A 30 gallon tank yields about 21 gallons of shower-temp water. So that 8 minute shower is about it. For a 1200 sq.ft. house, presumably 2 baths? 30 gallons is woefully undersized, especially electric. Do you have only that one water heater??

Be sure you have a dual element unit with 4500 watt WORKING elements. Set the temp higher also. You could go to 5500 watts if the wire will allow it. I have a 30 gallon unit that I rigged both 5500w elements to run concurrently, and I set the lower element temp higher, and insulated it greatly.

Works like a tankless flow thru unit now.

Some low boys have only one element. And be sure you have 240 volts to the heater. They work fine but slow on 120v. A very little known fact.

thanks, I will check each out when I get some time off, never thought about the volts pretty sure I have 110 going there