Woe #47: It's freaking impossible to cut a perfect circle.

I'm trying to be as crafty and low cost as possible with some decorations for our wedding.
For example, I am making banners to hang up in some locations.
Like over our gift gazebo, on the thank you gift cart, and on the front entryway table.
I'm talking about banners like this:

Cute right?
I even bought some cute paper to use and everything!
I really don't like the square banner look;
the circular one just looks more classy and cuter to me.
And it doesn't look like it takes up as much hanging room/space.
Only problem?
Woe #47: It's freaking impossible to cut a perfect circle.
How the hell am I supposed to cut out 26 perfect circles to make adorable banners?
No idea.
Your guess is as good as mine.
I thought the copy center might be able to help me out, but to no avail.
I'm on my own for this one.
And I keep putting it off because the idea of uneven, not the same size circles for my banners stress me out.
I'm kind of a perfectionist, you know.
Any ideas?