I don't know if it's just the Avery software of what but these do not print the way that you see them on screen. It's incredibly frustrating when something is centered and there should be no problem with it printing centered on both the front and back but the cards end up overlapping and you can't print doubled sided because they just don't print right. I never have this type of problem when I print regular index cards or word/pdf documents so I'm going with its an Avery software glitch but as long as you print one-sided they're OK.
I wish that you can fulfill all your dreams and goals in life. The best wishes one can wish are that those you love experience success in all their endeavors and are granted the fruition of their lifelong dreams. May your birthday be the window which opens a million vistas that help you in the fulfillment of your dreams and accomplishments of your goals!