How long would a guy usually take to call or text you?

Hi so there's this guy I like who I think might like me, he asked my friend for my number before but she didn't want to give it without my permission so I gave it to his friend yesterday to give to him, I'm not sure if he gave it to him or not but he put it in his phone, anyways I know I only gave it to him yesterday but I heard there's a " 3 day rule " I'm just nervous that he won't text or call me, do you think it's too soon for me to worry?