Worried about preschool

My son is 2 1/2 and we just found out he got accepted into preschool, he turns 3 August 4th, and then starts school August 13th I think he will be one of the youngest there. I am so nervous about how he will do, he doesn’t listen very well, and I’m afraid they will have a hard time with him, and he won’t want to sit at lunch and eat like he’s supposed to, or stay in the line, or things like that when he’s supposed to. My mom keeps telling me that kids act completely different at school versus when they’re home so he will probably do just fine. I’m just so worried I want him to go but I don’t want him to if he’s not ready yet.😩 I also feel like maybe this is what will help him with listening and talking a lot more and stuff like that.