If you want to install it now use windows 10 update assistant it will install it not the media tool .
open https://www.microsoft.com/en-us/software-download/windows10 you will find windows 10 april 2018 then click update now it will download assistant and then it will search for update and find windows 10 1809 the click update now but I am not responsible if any issue occur to your device. I also need to make update now but all comments say that it may cause issues to computers and laps ….So now it is your opinion