Nintendo released Pre-load downloadable data for digital versions of Fire Emblem if’s three versions in Japan about a month before its release in Japan. Nintendo is now doing the same for those in North America.
Image cited from NintendoEverything.com
You can purchase and download most of Fates now, with only a small update required on launch day to begin playing.
Do be aware, the eShop page recommends not purchasing both and downloading both individually:
“Please make sure not to purchase both Birthright and Conquest at full price on Nintendo eShop. To purchase second path at a discounted price, please select the Explore Fates option that appears at the beginning of Chapter Six, or purchase a download code at retail to redeem within the in-game shop Dragon’s Gate.”
And if you haven’t already, you may want to add both male and female Corrin to your Super Smash Bros for Wii U and 3DS roster. Corrin is now available for download from the Nintendo eShop for $4.99 (for Wii U or 3DS) or $5.99 (for both).
Corrin is included in several more pricey bundles, which include a small handful of soundtracks and trophies of Ryoma and Xander.