Can i miss out on any changes if dont start hrt now??

so im 18 and i can start hrt anytime i want since i already got the gender dysphoria diagnostic from my psychiatrist which is the only requirement in my country but im not sure if i want to start it now. im also afraid that in the future i might regret not starting as soon as possible, so what can i miss out on if i start at 20, for example, instead of now, at 18?