It's a large trackpad, yes.
I did a quick search online for keyboarding posture recommendations. Spurious inputs aside, most guides appear to recommend that your wrists be floating (or be otherwise supported) above the keyboard. I guess I'm subtly suggesting that you might be typing a little unconventionally, but in reality, I have no idea, and please don't take this as any kind of personal attack. Here's an example of one of the many keyboarding guides online:
http://www.workwhilewalking.com/wp-content/uploads/2013/09/bigstock-male-hands-t ype-on-keyboard-257583201.jpg
I'm typing this on my own 13" recent-model MacBook Pro which, like your computer, has an expansive trackpad. Personally I'm a fan of it because it has lots of space for gestures/scrolling/clicking, etc. I've never had an issue with inadvertently clicking or moving the pointer while hitting the space bar.