Is it not good to text back right away to your crush?

The guy I have crush on text me and sometimes I am busy but I do wait a while maybe like 10 to 40 minutes before I text him back... is that not good? or is it good to text back right away? What is good way to get him, wait and text or text back right away? but he did say he doesn't like playing games.. but it could be that I am busy also. what's the best to get the guys attention.. to make him wait or text back right away is better?