Bigger... is a good bit different from
Beyond...However, each guide is created to prepare the child with the skills he/she needs to move on to the next guide. So, no matter if you go full-speed or slow it down to half-pace, your dd should be able to handle
Bigger...when the time comes. We loved both guides, by the way...even my oldest son would want to listen to the readings for
Beyond... and he did great with
Bigger... plus extensions. We personally used
Beyond...for 2nd grade, because I didn't even know about
Little Hearts... then. However, for my youngest son we will be using
Beyond.. at half-pace, partly b/c he is going to be using it beginning in 1st grade but also b/c a toddler and then a newborn in the fall is going to require that I slow down a bit. You could do either and it would be fine. If the placement chart shows that your dd fits right into
Beyond...and you have the time, then I say forge ahead full-speed and you should have a great year.
You'll learn a ton, as well as your daughter!

Besides, you can always slow down to half-pace later if need be for any reason. HTH