Questions, Comments, Concerns???

I am getting very nervous, maybe it is normal mommy worried stuff but I am very nervous about aiden starting "school". He is signed up and supposed to start going to Bible school 2 days a week the beginning of september.  He goes from 9:30-2pm on tuesdays and thursdays and he will learn bible songs and stories, have chapel, have lunch, have play time, and rest time and then come home. I just feel like he's too small for this. I have to pack him a lunch that he can eat all by himself, get him a backpack and  a nap mat. I just don't know if he's ready, or if I'm ready. I just don't know. I have known this was coming but it wasn't until yesterday when I actually started thinking that I need to go purchase these things that I started to feel apprehensive about it. The other part is that he will be in the "18 month old" class which is the youngest they start and he won't quite be 18 months. He will be 17 and not that I think that ONE month is that much of a difference but that means there will be kids in his class who are 18, 19, 20, 21 months? I don't want him to be behind. I don't want every other kid to be able to follow instructions and sit still and listen to stories and Aiden can't do that. I know that aiden is a bit behind on his verbal skills or at least he was, he seems to be catching up quickly and maybe being around more kids will really help him. I have thought of trying to hold him out until january but then his class will have already been together for several months and again...I don't want him to be behind or left out cause he didn't start when the other kids did?? I just don't know. Is it normal for me to be having this many doubts? I said he was going to start school in september, I should stick to that right? A little separation would probably be good for us both. I also feel like I have a race now. I need to get him off his bottle before he goes, I need to make sure he can eat lunch on his own without my help or babying him or letting him eat and run around...what kind of things do you even pack in an 18 month olds lunch? Is he supposed to be able to sit down with a sandwich and eat it whole? Cause he can't/ won't do that. He will take the sandwich apart, rip it up, throw the pieces on the ground and then try to eat the pieces off the ground...oh my so much work to do!