First sleepover

So husband niece (f23) lives with her boyfriend (they are together for 3 and half years he is m27).

Now i have son WHO is 2.5

years old.And they want him for sleepover.

Now only time he had sleepover was on vacation since he already falled asleep at my sister In law house.And he really loves her so I didn’t want to wake him up then so I left him there and went back and came next morning and he was still sleeping.

Now niece is asking me several times to let him for sleepover.I’m not really ready.

I know them both and I really love them but I have read so many stories about sleepovers at family and what was happening I know they wouldn’t do that but I’m still afraid.

I had something happened to me when I was kid but not on sleepover and not from family member but I still remember that.

Idk maybe is irrational fear but it’s there.

I told them he will have sleepover but when he is little bit older.

Forget to add they will take him for couple hours to go to park fair to their house so he can play with dog.

Both of them love my son and he really loves them.They are calling every day on face time to see him.

And I’m also 27 years old.