iPhone 5 Guest List Date Picker

Here's a concept for a guest list where you pick the date and create the list. The calendar would be collapsed by default, but you could tap the calendar icon to reveal (slide out) the calendar. Please checkout the FULL resolution version attached.

I'd love to hear what you all think - are the date tiles too small to tap? Is the spacing right? Does the checkmark work?

The typeface is my new favorite: Ubuntu. The awesome wooden background is by the great Matthew Skiles: http://dribbble.com/shots/31901-Hand-Crafted-Wood-Texture.