MamaMary,
I ordered Bigger...and Little Hearts. My little one is 4 (he'll be 5 in June) and he's been asking to "do school". So, I thought I'd go ahead and get all of it, and start with him going very slowly, to stretch it all the way through next year, too. Bigger... I'll be doing with my 8 and 10 year old, using the extension pack (via the library) with the older one. I got the devotional God's Hand in Life's Little Moments, too, so I'm excited about that.
I still need to look through each book more carefully to make sure they are a good fit, but I don't think there will be much of a problem. We will be using Singapore Math- we made the switch so they will all be in the same program. And I also ordered DITHOR for my older kids. I will not be able to start BHFHG until we finish the program we are in now, so it will be around July, probably. I have to wait!
But, I figure I will have looked through the books enough by then that I'll know exactly what I'm doing.
I used BLHFHG with my daughter last year for 1st grade so I'm somewhat familiar with HOD. We really liked it, but switched because I was trying to get something more exciting for my son. I should have looked more carefully at Bigger for this year, but you know how that goes.
Now, we're back on track, and I can't wait to get started!
My HOD boxes came in the mail today and I did a happy dance at the front door. My mom laughed at me. Later, the UPS man (no I didn't attack him, though it took much self-control 
We looked through the books together and he wanted to begin his Math book right then. But, I told him we need to wait 'til Nana and Paw-Paw go home. I need the time to get everything organized, and to decide exactly how we're gonna do this! 
I should be ready by March 3rd? Anyway, I just had to share how overjoyed we all are to get our new things. I can't wait to get started with the new devotional, too. And, of course, to show DH when he gets home tonight. Thanks again for all of your help and support, ladies! And a very special thanks to Mike and Carrie for getting my order to me so quickly, as well as the personal phone call to clarify my order. You guys are awesome!
I'll pass your thanks along to my hubby as he's the one who works hard to get everyone's items out as soon as possible! 
Ok getting silly but really just sort of get things a little organized and doing is what gives you the assurance that it really is pretty easy.