2009 Jeep Patriot has a rough start.

Hi everyone.

So I just bought a 2009 Jeep Patriot. Ive had it for a couple of weeks now
and it was running totally fine. But earlier today after I got home from work,
I forgot I had to run the rent money to my landlord's office. So I hopped
back in my Jeep and turned the key. As I did so, I noticed that the start was
much more rough than I remembered [or noticed] before. After the initial
rough start, the jeep runs fine. I haven't ran voltage tests on it yet but I
soon plan to when I get the meter for it. I did this a couple more times over
and over and the "roughness" persisted. It hasn't died on me yet. The
motor only has 45k on it and I haven't done anything strenuous with it yet.
I'm curious if this is a common problem with my make and model or if this is
something like a starter issue or battery issue. Please help! I'm frustrated at
the thought that my new car is already starting to cause me problems...
GRRR!