Paddle Question from a newbie

[Bass-Man]

Hey everyone, I'm a newbie to the world of Yak's .I'm thinking of buy a Ascend FS 12 T sit on from Bass Pro any input on this yak would be a big help. It will be a back up to my boat not my main fishing platform. It will be used on ponds and bogs only no current or wakes to worry about. I'm 5' 7" about 170lbs from what I read a 12 foot is the way to go. I will be mostly fishing for Large mouth Bass and pickerel. Fly fishing with a 5wt,7wt and 9wt the 7 and 9 are both 9' long for casting rods will be 5'6'' to 7' long. My question is about the paddles I see they mostly come in two sizes 220cm and 230cm or 86 1/2" and 90 1/2" what is the big deal in an extra 4"? Like I said any and all information will be greatly appreciated big time. I know there are better yaks out there better then the Bass Pro one but the price and features are in line what I want to spend about $500.00 bucks or so.
Thanks
Mike