Help!?!

Okay so I asked my man “what am I gonna be working with 😉” since we were sexting and I wanted to know he told me he was a 7 inch and then he proceeds a few days later to say “I hope you don’t see me when I’m soft” and I asked why and he said because he is a 3inch soft and 7 inch while hard. Now I have never seen or touched a dick other than one dick pic I’ve gotten so I don’t know if that’s normal. I know that the size of the 🍆 grows when if becomes erect but 4 inches!?! Does this sound right orrr??? I’m so confused it doesn’t seem like it would grow 4 inches by just becoming erect. Can someone explain. Yes I am young and I have no experience soo please help 🙏🏼