is this normal ?

Hello guys, when I started nofap i did not have any urges from the day one till day 22,i was working out daily (weight lifting), have a good sleep pattern and good diet) then i started to have urges and I watched porn for like 2 days (1 to 2-hour session) but did not masturbate, then I decided to not do that as well and i stopped, so after 2 days of again not watching porn now again I am having no urges neither boner or erection,

Now my question is, why didn't have any urges for even the first 48 hours when i started nofap, and 2nd why they are gone after day 24 as well? anyone have any idea or know the science behind it please share your opinion, I will be very appreciative to you

Note: sorry for my bad English