Vera Bradley Tech Backpack as personal carry on bag on airplanes

I need to fly for work next week. I plan on taking only two carry bags with me. I have a wheeled piece of luggage for my clothes, shoes, etc. And I bought a Vera Bradley tech backpack for my personal carry on that I plan to carry my laptop, phone, IPad, toiletries in. I thought that the backpack was a standard size for flying but I just looked on the United Airlines site and it said your backpack must be 9x10x16 inches in size. My Vera Tech Backpack is 6 1/2 x 11 1/4 x16 inches in size, which means it is 1 1/2 inches too wide. Will this mean that I will need to check the bag or will they ignore the extra 1 1/2 inches? I don't want to have to check the bag if it has my laptop in it.