Copy your savefiles with JK's Save Manager. I did that for a friend who was migrating his 2DS to his new 3DS.
It was a pain in the arse because it took way too long to do so.
Also, install arm9loaderhax (a9lh) on your new 3DS. The process is much easier now, and much safer (you inject a ready made nand to the system, get your OTP, and inject your original nand back, and set up Luma3DS).