Sucking dick

The first time I tried sucking dick I was laughing really hard trying to cover up my nervousness.. and told him I couldn’t. Anyways my new partner hasn’t told me in bed or in person he wants me to suck his dick but I think he finally indicated he wants me to. I’m kinda scared still because I have a small mouth and I feel like my teeth will get in the way and my jaw also pops when I open it too big.. and again I have never sucked dick cause I got too scared laughed and said I couldn’t.