Is my design too simple?

I think having the 'ORGanimal is' below the fold could be an issue.

I kinda got that it was a calendar for pets, but wasn't sure exactly what the deal was.

I don't think your design is too simple. But I think you might want to take a closer look at the flow. What people see and how they understand what they are supposed to do.

It's cutting it close. I generally like simple, spare designs but many people don't. One problem I think are the typestyles. I think a sans-serif font would look better (Arial, Helvetica, Tahoma, Verdana, Trebuchet, etc.).

Typo: "an application that let's you manage all your pets in one place" should be "an application that lets you manage all your pets in one place" (keyword: let).

I didnt look on the content, just the design. I like it how simple it is, but the background annoyed me a bit. I got distracted from it.