Whyyy?

Does anyone else have this problem or Is it just me? When I’m talking to a normal guy friend we can talk for ages like literally I’ll have them laughing their asses off and enjoying their time with me. But when it comes to talking with my crush it’s like I don’t know how to talk. My mind goes blank and nothing pops up in my mind. Does anyone go through this. It’s like I don’t know if the things that I say will be funny to him because he is 11 years older than me. Anyone?