I was talking recently with one of the group leaders at The Big Sis’ after-school program. She is not The Big Sis’ leader, but sometimes she’ll sub in her group and I’ve seen her fairly regularly since the beginning of the school year. I try to pick up The Big Sis first (it’s a whole lot easier logistically that way), but when I worked at my last job, it made more sense to pick up The Little Sis first (daycare was two blocks from my office) and then pick up The Big Sis (her after-school program is two blocks from our house).
Anyway, all of that is to explain that this Other Group Leader has seen The Little Sis several times, and we were chatting about sibling age differences, with me pointing out how wonderful and helpful The Big Sis is with The Little Sis. The Other Group Leader said with a laugh, “Wow, you sure did plan that timing right, didn’t you?”
And maybe I should let it go now, but I just can’t help myself. I don’t usually volunteer the information unless it’s relevant, but I found myself saying, “Well, I wouldn’t exactly say that timing was planned on purpose. She took two years to conceive, so…yeah…didn’t really plan for 4 1/2 years apart. But it’s worked out very well indeed.”
She didn’t miss a beat, though, and proclaimed with a genuine smile, “Ah, so she’s a blessing baby, then. Very nice.”
And she is. She truly is.
And Baby B Makes Three! 
That’s a great way to handle it, both on your end and the teachers end