First, congratulations on both grandchildren! It sounds like you're overwhelmed with photos, and you need to make some choices. What I would do is pick 10 or so absolute favorites and start there. You can always put the other pictures in a regular photo album. If and when you decide to use them in a scrapbook, they will be ready. You might also want to consider the divided page protector options available now, such as Project Life or Simple Stories. You can find many options at Scrapbook.com: Scrapbooking Ideas & Supplies
and Amazon. Good luck and have fun!