Is it really the end of May?!

I have, um, 25 days until Zach turns 5, and only 23 until his birthday party. I've been putting off really planning and sending out invites to his party all month thinking, "No, I don't have to do it now, I have plenty of time." But I don't! I have to get in the invites to his school friends TOMORROW because that's their last day of school and the school's not allowed to give out addresses and phone numbers. Probably I shouldn't have put off sending those...
Which leads to a new set of worms. What do I do if none of Zach's friends can come to his birthday party? This is his first real one and he'll be devastated if none can come, and I won't even be able to call in backups because I can't reach anyone. Or what if they come and they're mean? One of the little boys he wants to invite has been mean to him lately (or so Zach was saying, now he's saying he wasn't), and I've never heard him talking about playing with two of the other boys. I've only ever heard him talking about playing with and being friends with two of the boys he's inviting. On top of that, he won't invite any little girls from his class. Wouldn't be an issue except his best friend in his class is a little girl, and he said no girls can come, not even her.
But if his friends do come what do I do about the parents? John and I are so much younger than almost all of the other parents, for the most part about 5-10 years younger. We won't have much in common with them at all. Maybe I can talk my mom into coming and acting like Zach's mom. She's young enough to pull it off.