I'm kinda confused

So I am to young to have a bf not ready to go there yet I like this guys and we can text for hours at a time but I have to text him first he never starts a conversation he will keep it going or if we stop in the middle he will pick it back Something I should have mentioned I when I was a lot younger I was close to his younger sister not anymore but any ways what do you think he is he interested is he just being nice because i started the conversation or because i know his younger sister