This is confusing because the lengths are neither exactly the same nor are they really different. Click on the invitation to change its alignment. However it is often better to align to the left or the right because the hard vertical edge makes a stronger statement. Decisions about alignment need to be made consciously because different kinds of alignment produce different effects. One exception is continuous text, which should always be aligned vertically.
Formal invitations are often center aligned.
Using left alignments changes the look of the page. It looks more unified and and dramatic, but it is also less formal. When you select an alignment, be sure that it gives you the look you're after. Now some elements will be distant from others, but they will be seen as part of the whole if you apply the Principle of Alignment . For more ideas about page design try using the Principles of Repetition and Contrast.